Bringing My '79 Bonneville Special Back to Life
- Thread starter Tulsaalva
- Start date
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- 169
Renaming threads
You're right, Grandpaul. I'm a moderator on another discussion board. One of my duties as such is to rename threads that need it. So often folks will name a thread, "Hey, there!" or something similar. I have to read the posts and change the name to something more appropriate.
Al
You're right, Grandpaul. I'm a moderator on another discussion board. One of my duties as such is to rename threads that need it. So often folks will name a thread, "Hey, there!" or something similar. I have to read the posts and change the name to something more appropriate.
Al
- Joined
- Sep 3, 2007
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- 169
Setting the Front Master Cylinder
I've gone back and readjusted the master cylinder in accordance with L.A.B.'s suggestion.
When backing off the cylinder, air first starts to flow when the groove that accepts the grub bolt is 180 degrees off. The instructions say to continue to back the cylinder off a complete turn but to line up the groove with the grub bolt. Therefore I have a choice of backing the cylinder off one-half turn or one and a half turns in order to screw in the grub bolt.
Since air seems to flow freely at one-half turn after air first begins to flow, that's the way I've set it so far. If the additional turn is necessary, I can easily make the change.
Opinions, please?
Al
I've gone back and readjusted the master cylinder in accordance with L.A.B.'s suggestion.
When backing off the cylinder, air first starts to flow when the groove that accepts the grub bolt is 180 degrees off. The instructions say to continue to back the cylinder off a complete turn but to line up the groove with the grub bolt. Therefore I have a choice of backing the cylinder off one-half turn or one and a half turns in order to screw in the grub bolt.
Since air seems to flow freely at one-half turn after air first begins to flow, that's the way I've set it so far. If the additional turn is necessary, I can easily make the change.
Opinions, please?
Al
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Tulsaalva said:
(Log in) Select the thread, then click the "Edit" button of the first (your) message, if the original subject title shows in the "Subject" box above the message, then you should be able to edit it? Others have done so to correct typo's etc. (or I could do so, if you'd like to say what you'd like to rename it?)
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Re: Setting the Front Master Cylinder
I think you will be OK.
The revised instructions say this:
_____________________________________
"1. Draw a pencil line on the underside of the cylinder in line with the centre of the flat machined on the body. Later cylinders will have a slot machined in the centre of the flat.
2. Making sure that the pushrod enters the hole in the boot, screw the cylinder into the bracket moving the lever slightly so as to feel when all the last movement is eliminated. Do this very carefully so that all movement is just removed.
3. With all movement eliminated, note the position of the reservoir in relation to the tapped boss [a diagram included within instructions identifies that as being the mirror mounting boss] on the bracket. From this position screw the cylinder in one complete turn so that the reservoir finishes up in the same previously noted position.
4. Continue screwing in the cylinder the part of a turn necessary to bring the reservoir vertical so as to line up the tapped boss. Do NOT unscrew the cylinder to line up-always screw IN the part turn necessary even if it is almost a complete turn of 360 degrees.
5. Make a further slight turn inwards to align the hole for the set [grub] screw with the centre of the flat, or slot, denoted by the pencil line. Fit the screw (ideally apply Loctite CV) and torque up 2.26 Nm-20 lb. ins., making sure that on cylinders with a slot machined in the body that the screw locates properly into the slot."
________________________________
Tulsaalva said:
I think you will be OK.
The revised instructions say this:
_____________________________________
"1. Draw a pencil line on the underside of the cylinder in line with the centre of the flat machined on the body. Later cylinders will have a slot machined in the centre of the flat.
2. Making sure that the pushrod enters the hole in the boot, screw the cylinder into the bracket moving the lever slightly so as to feel when all the last movement is eliminated. Do this very carefully so that all movement is just removed.
3. With all movement eliminated, note the position of the reservoir in relation to the tapped boss [a diagram included within instructions identifies that as being the mirror mounting boss] on the bracket. From this position screw the cylinder in one complete turn so that the reservoir finishes up in the same previously noted position.
4. Continue screwing in the cylinder the part of a turn necessary to bring the reservoir vertical so as to line up the tapped boss. Do NOT unscrew the cylinder to line up-always screw IN the part turn necessary even if it is almost a complete turn of 360 degrees.
5. Make a further slight turn inwards to align the hole for the set [grub] screw with the centre of the flat, or slot, denoted by the pencil line. Fit the screw (ideally apply Loctite CV) and torque up 2.26 Nm-20 lb. ins., making sure that on cylinders with a slot machined in the body that the screw locates properly into the slot."
________________________________
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Bonneville Front Disc Brake
The Bonny has a front brake. It is strong and it is smooth! Yeeeehhhhaaaaa!
I had to go back to Tulsa Brake and Clutch to get another banjo bolt and six copper washers. Unfortunately, the shortest banjo bolt they had was too long for the Triumph. The fellow at TB&C asked if I knew a machinist.
"Yes, I do," I told him. "My neighbor across the street has built a wonderful machine shop in his back yard with several computerized lathes, milling machines, and tools I don't even understand."
"He runs a business from his back yard?" asked Mr. TB&C.
"Oh, no! His shop is just for his hobby."
"What's his hobby?"
"He makes cannon."
"I'm sorry, I though you said,'he makes cannon.'"
"Yes, big ones, little ones... Do you need a cannon?" (Oklahoma does have a "concealed carry" law, y'know?)
"Nope! But I guess he can shave the end off a banjo bolt."
Indeed he could... and did. He did a beautiful job.
However, it turned out that the back brake also needs a shorter banjo bolt on the caliper so I don't have a rear brake yet. Worse, I destroyed the one banjo bolt that was too long. So tomorrow I have to go back to TB&C for another.
I printed your new method for setting the master cylinder, L.A.B., and make it a permanent part of my factory manual. I didn't change what I'd done previously, though, but it will be there for next time. Thank you!
Al
The Bonny has a front brake. It is strong and it is smooth! Yeeeehhhhaaaaa!
I had to go back to Tulsa Brake and Clutch to get another banjo bolt and six copper washers. Unfortunately, the shortest banjo bolt they had was too long for the Triumph. The fellow at TB&C asked if I knew a machinist.
"Yes, I do," I told him. "My neighbor across the street has built a wonderful machine shop in his back yard with several computerized lathes, milling machines, and tools I don't even understand."
"He runs a business from his back yard?" asked Mr. TB&C.
"Oh, no! His shop is just for his hobby."
"What's his hobby?"
"He makes cannon."
"I'm sorry, I though you said,'he makes cannon.'"
"Yes, big ones, little ones... Do you need a cannon?" (Oklahoma does have a "concealed carry" law, y'know?)
"Nope! But I guess he can shave the end off a banjo bolt."
Indeed he could... and did. He did a beautiful job.
However, it turned out that the back brake also needs a shorter banjo bolt on the caliper so I don't have a rear brake yet. Worse, I destroyed the one banjo bolt that was too long. So tomorrow I have to go back to TB&C for another.
I printed your new method for setting the master cylinder, L.A.B., and make it a permanent part of my factory manual. I didn't change what I'd done previously, though, but it will be there for next time. Thank you!
Al
- Joined
- Sep 3, 2007
- Messages
- 169
Rear brake rebuild
Thanks for the group hug, Grandpaul. I'm real proud of the front brake, considering this is the first time I've worked on it on a Bonneville.
The rear brake, however, is proving somewhat more challenging.
On page F-12 of the factory manual, in the first paragraph, the following is written:
"The rear brake master cylinder is a sealed unit and is only serviced as such. The principle of operation is identical to that of the front master cylinder with the exception that the reservoir is mounted remotely beneath the twinseat."
So, does that mean that I cannot rebuild the rear master cylinder, and must replace the entire unit for $220.00? I have a master cylinder rebuild kit that I bought from Jack's Motorcycles here in Tulsa. LaNelle, the owner for the past forty years or so, is quite good at ordering parts but has never worked on bikes. (She is the city's best wheel truer.) She no longer has a mechanic employed. He died several years ago. LaNelle thought that the two master cylinders use the same rebuild kit but has double-checked and has found no listing for a rebuilt kit specifically for the rear master cylinder. She can order a new rear master cylinder but does not have it in the store. "Too expensive to keep in stock," she said.
The factory manual has no information on the rebuilding of the rear master cylinder.
So I decided to use the old rear master cylinder. The old one seemed to be pumping. I replaced everything else except the remote reservoir and the master cylinder itself. The cannon guy across the street machined two more banjo bolts to fit after I ground a hole in my right thumb nail trying to save time. It was a neat installation with no leaks.
So I went about the bleeding job and have not been able to build hydraulic pressure in the system. There is enough pressure to slightly move the pads when pumping the brake, but never enough to create even a small amount of drag on the brake disc. When bleeding, the air bubbles come out one or two at a time, never a good solid spurt. A bad omen is that the small amount of fluid that does come out is an ugly brown color, probably rust from the old master cylinder I used. Bad choice.
Where do I go from here, my friends?
Al
Thanks for the group hug, Grandpaul. I'm real proud of the front brake, considering this is the first time I've worked on it on a Bonneville.
The rear brake, however, is proving somewhat more challenging.
On page F-12 of the factory manual, in the first paragraph, the following is written:
"The rear brake master cylinder is a sealed unit and is only serviced as such. The principle of operation is identical to that of the front master cylinder with the exception that the reservoir is mounted remotely beneath the twinseat."
So, does that mean that I cannot rebuild the rear master cylinder, and must replace the entire unit for $220.00? I have a master cylinder rebuild kit that I bought from Jack's Motorcycles here in Tulsa. LaNelle, the owner for the past forty years or so, is quite good at ordering parts but has never worked on bikes. (She is the city's best wheel truer.) She no longer has a mechanic employed. He died several years ago. LaNelle thought that the two master cylinders use the same rebuild kit but has double-checked and has found no listing for a rebuilt kit specifically for the rear master cylinder. She can order a new rear master cylinder but does not have it in the store. "Too expensive to keep in stock," she said.
The factory manual has no information on the rebuilding of the rear master cylinder.
So I decided to use the old rear master cylinder. The old one seemed to be pumping. I replaced everything else except the remote reservoir and the master cylinder itself. The cannon guy across the street machined two more banjo bolts to fit after I ground a hole in my right thumb nail trying to save time. It was a neat installation with no leaks.
So I went about the bleeding job and have not been able to build hydraulic pressure in the system. There is enough pressure to slightly move the pads when pumping the brake, but never enough to create even a small amount of drag on the brake disc. When bleeding, the air bubbles come out one or two at a time, never a good solid spurt. A bad omen is that the small amount of fluid that does come out is an ugly brown color, probably rust from the old master cylinder I used. Bad choice.
Where do I go from here, my friends?
Al
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Re: Rear brake rebuild
And one of the great Triumph mysteries of all time: "The non-rebuildable master cylinder that never was!" Or was it?
The rear master cylinder *supposedly* became a sealed unit from Sept. 1977-onwards, "due to a change in manufacturing procedure" -according to Lockheed's Service Sheet? However, I've never heard of any Triumph owner finding they have this non-rebuildable rear master cylinder? Has anybody else heard of, or seen one?
If the factory did fit them from late '77-on, then my own low mileage June '78 manufactured T140V ought to have one, and it doesn't?
So as far as I am concerned, if you are able to dismantle your rear unit then it can be rebuilt using the standard seal kit.
Tulsaalva said:
And one of the great Triumph mysteries of all time: "The non-rebuildable master cylinder that never was!" Or was it?
The rear master cylinder *supposedly* became a sealed unit from Sept. 1977-onwards, "due to a change in manufacturing procedure" -according to Lockheed's Service Sheet? However, I've never heard of any Triumph owner finding they have this non-rebuildable rear master cylinder? Has anybody else heard of, or seen one?
If the factory did fit them from late '77-on, then my own low mileage June '78 manufactured T140V ought to have one, and it doesn't?
So as far as I am concerned, if you are able to dismantle your rear unit then it can be rebuilt using the standard seal kit.
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One extra thing to remember with the rear Lockheed master cylinder is not to disturb the the two nuts that are locked together on the pushrod unless it is completely necessary.
If the nuts have been moved, then the distance between the face of the large nut with the groove for the boot and the alloy casting must be set to between 8.9-9.4mm (0.35"-0.37") with the pushrod set in the brake fully off position.
If the nuts have been moved, then the distance between the face of the large nut with the groove for the boot and the alloy casting must be set to between 8.9-9.4mm (0.35"-0.37") with the pushrod set in the brake fully off position.
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Too late, L.A.B., I've already disturbed them is search of a way to disconnect the brake pedal return spring. The factory manual does cover the resetting of the nuts.
However, the manual says: "Disconnect the brake pedal return spring then remove the nut and washer and withdraw the master cylinder operating lever.:
How does one "disconnect the brke pedal return spring."?
Wait! I just discovered Section E6!! "Removing and Servicing the Rear Brake Pedal Spindle." There's even a diagram!
Okay! Here I go to remove the brake pedal!
Al
However, the manual says: "Disconnect the brake pedal return spring then remove the nut and washer and withdraw the master cylinder operating lever.:
How does one "disconnect the brke pedal return spring."?
Wait! I just discovered Section E6!! "Removing and Servicing the Rear Brake Pedal Spindle." There's even a diagram!
Okay! Here I go to remove the brake pedal!
Al
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Tulsaalva said:
That actually refers to the brake pedal nut and washer at the inner end of its pivot which holds the operating lever on the squared end of the spindle, and is nothing to do with the two pushrod nuts mentioned previously, as the operating lever has a trunnion which is locked to the pushrod by the two trunnion locking nuts that are used to set the pedal height?
That return spring is difficult to refit!!
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Rear Master Cylinder Clean Up
I'd like to have those instructions to add to my factory manual, L.A.B.
The rear master cylinder is cleaned and back together. I can't say It's been rebuilt because all the parts needed were not included with the front master cylinder kit that I had and used. If the parts were included I used them, of course. If not, I cleaned them thoroughly and reused them. The one rubber part that was torn and not usable was included in the kit. Pretty lucky, that!
The inside of that master cylinder was a sight to behold! I'm talking serious crud! The three ports in the piston were not totally clogged but were mighty close to it! The holes that admit fluid from the reservoir were also close to clogged.
I had a terrible time getting the spring, piston, etc., assembly out of the cylinder! Even after I dug through the thick rusty mud, found the snap ring (which was not properly seated) and removed it, I couldn't get the assembly to slide out. Even 120 pounds of air pressure didn't budge it. Finally, I found that a deep 11MM socket fit the bore perfectly. I inserted it and tapped it gently with a small hammer. I guess the vibration and constant movement of the spring up and down finally ate away the crud allowing the assembly to eventually become dislodged and come out.
I scrubbed the parts in DOT 4 with a toothbrush, scotchbrite and an emery board stolen from my wife's fingernail polish kit, being careful not to score or damage the metal parts but to remove and polish away the rust deposits. After this step I poured the rusty muddy brake fluid into a recycling container, cleaned the wash pan, and did the operation all over again in clean brake fluid. I'm fairly pleased with the results, but if I had known what was inside that master cylinder, I'd have seriously considered ordering a new one!
I reassembled it exactly the way it came apart, installing the snap ring properly this time, and screwed the male portion into the female part to the point where it was before disassembly. The grub screw was no problem to fit.
The master cylinder had two wave washers installed but the rebuild kit came with an equally thin but not wavy single one. I used the new flat washer as I had done on the front master cylinder. I hope that was not a bad decision.
Tomorrow I plan to install the master cylinder on the bike, clean the brake line and caliper, and bleed the system.
I do have a bit of foreboding about the spring and lever adjustment so any tips would be gratefully accepted.
Al
L.A.B. said:
I'd like to have those instructions to add to my factory manual, L.A.B.
The rear master cylinder is cleaned and back together. I can't say It's been rebuilt because all the parts needed were not included with the front master cylinder kit that I had and used. If the parts were included I used them, of course. If not, I cleaned them thoroughly and reused them. The one rubber part that was torn and not usable was included in the kit. Pretty lucky, that!
The inside of that master cylinder was a sight to behold! I'm talking serious crud! The three ports in the piston were not totally clogged but were mighty close to it! The holes that admit fluid from the reservoir were also close to clogged.
I had a terrible time getting the spring, piston, etc., assembly out of the cylinder! Even after I dug through the thick rusty mud, found the snap ring (which was not properly seated) and removed it, I couldn't get the assembly to slide out. Even 120 pounds of air pressure didn't budge it. Finally, I found that a deep 11MM socket fit the bore perfectly. I inserted it and tapped it gently with a small hammer. I guess the vibration and constant movement of the spring up and down finally ate away the crud allowing the assembly to eventually become dislodged and come out.
I scrubbed the parts in DOT 4 with a toothbrush, scotchbrite and an emery board stolen from my wife's fingernail polish kit, being careful not to score or damage the metal parts but to remove and polish away the rust deposits. After this step I poured the rusty muddy brake fluid into a recycling container, cleaned the wash pan, and did the operation all over again in clean brake fluid. I'm fairly pleased with the results, but if I had known what was inside that master cylinder, I'd have seriously considered ordering a new one!
I reassembled it exactly the way it came apart, installing the snap ring properly this time, and screwed the male portion into the female part to the point where it was before disassembly. The grub screw was no problem to fit.
The master cylinder had two wave washers installed but the rebuild kit came with an equally thin but not wavy single one. I used the new flat washer as I had done on the front master cylinder. I hope that was not a bad decision.
Tomorrow I plan to install the master cylinder on the bike, clean the brake line and caliper, and bleed the system.
I do have a bit of foreboding about the spring and lever adjustment so any tips would be gratefully accepted.
Al
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- Nov 20, 2004
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- 20,082
Re: Rear Master Cylinder Clean Up
OK Al, I will email them to you.
Actually, the assembly instructions are pretty much the same as for the front unit, the main difference being that the rear unit has a pipe connection for the remote reservoir for Triumphs, instead of the reservoir being mounted directly onto the cylinder barrel as on the front brake assembly, or the Norton 850 Mk III rear unit.
As far as I know, there should only be a single wave washer (between the piston and cup, see F8, Fig.13/Fig.14 diagrams in your manual) I don't know why you had two, unless the unit has been rebuilt before? Can you say what you meant when you said "I used the new flat washer as I had done on the front master cylinder." As I'd expect you to find a single wave washer in the front assembly, and one flat and one wave washer in the repair kit?
Generally, the repair kit contains enough parts to rebuild either one front or one rear master cylinder assembly, so you'd need two repair kits to do two cylinders properly.
Which means that you will have parts left over, some of which do not seem to fit anywhere? Those parts being a flat washer and a thinner secondary seal, as they are meant to be used with the very early front master cylinder pistons which were different.
So you should only replace like with like, although using the flat washer instead of the wave washer may not cause any problems? Personally, I'd want to change it for a wave washer, even if it meant using an old one, as they don't seem to deteriorate?
Setting the lever position on the pushrod should be a reasonably straightforward job?
As the adjustment of the lever trunnion really does no more than set the brake pedal height, just make sure it is set so there is a gap of at least 1/16" between the pedal and the footrest, with the brake fully off (manual F1 Fig.4)
You may find you need a 'spring pulling tool' (made from a length of wire, with a loop one end to hook on the spring, and pulling handle at the other end) in order to get the spring back on the lever?
_______________________________________
Also,
If you study the manual F8 Fig.14 sectioned diagram closely, you should see that the washer (item 7) is a dished type, which as far as I know was later replaced by the wave washer.
And another couple of things worth checking, is that the tiny pin hole in the rubber part of the new check valve (3) has actually been punched out? Also it is worth checking the spring (4) (not supplied in the repair kit) carefully for corrosion by bending it, once when I did that it distorted like a piece of soft wire where it had been attacked by corrosion!
Tulsaalva said:
OK Al, I will email them to you.
Actually, the assembly instructions are pretty much the same as for the front unit, the main difference being that the rear unit has a pipe connection for the remote reservoir for Triumphs, instead of the reservoir being mounted directly onto the cylinder barrel as on the front brake assembly, or the Norton 850 Mk III rear unit.
Tulsaalva said:
As far as I know, there should only be a single wave washer (between the piston and cup, see F8, Fig.13/Fig.14 diagrams in your manual) I don't know why you had two, unless the unit has been rebuilt before? Can you say what you meant when you said "I used the new flat washer as I had done on the front master cylinder." As I'd expect you to find a single wave washer in the front assembly, and one flat and one wave washer in the repair kit?
Generally, the repair kit contains enough parts to rebuild either one front or one rear master cylinder assembly, so you'd need two repair kits to do two cylinders properly.
Which means that you will have parts left over, some of which do not seem to fit anywhere? Those parts being a flat washer and a thinner secondary seal, as they are meant to be used with the very early front master cylinder pistons which were different.
So you should only replace like with like, although using the flat washer instead of the wave washer may not cause any problems? Personally, I'd want to change it for a wave washer, even if it meant using an old one, as they don't seem to deteriorate?
Tulsaalva said:
Setting the lever position on the pushrod should be a reasonably straightforward job?
As the adjustment of the lever trunnion really does no more than set the brake pedal height, just make sure it is set so there is a gap of at least 1/16" between the pedal and the footrest, with the brake fully off (manual F1 Fig.4)
You may find you need a 'spring pulling tool' (made from a length of wire, with a loop one end to hook on the spring, and pulling handle at the other end) in order to get the spring back on the lever?
_______________________________________
Also,
If you study the manual F8 Fig.14 sectioned diagram closely, you should see that the washer (item 7) is a dished type, which as far as I know was later replaced by the wave washer.
And another couple of things worth checking, is that the tiny pin hole in the rubber part of the new check valve (3) has actually been punched out? Also it is worth checking the spring (4) (not supplied in the repair kit) carefully for corrosion by bending it, once when I did that it distorted like a piece of soft wire where it had been attacked by corrosion!
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- Sep 3, 2007
- Messages
- 169
Rear Master Cylinder
Thanks for all the suggestions, L.A.B. I intend take the unit apart and use them as soon as I understand other problems. First some history on the bike.
The company I worked for in Germany sold the bike to an American serviceman. On his ride home, a car entered the road in front of him, causing him to have to brake hard and take evasive action. No accident occurred
The leading edge of the rear wheel went to the right in the swinging arm and hit the master cylinder, causing a loss of fluid. I'm not sure how that happened.
Meriden sent us a complete new assembly including rear swinging arm, tire, caliper, master cylinder, etc., all installed. They also discounted the bike because the customer insisted on a new motorcycle.
I bought the bike but resold it to another employee who eventually didn't pay me for it. I had moved back to the states in the meantime so he shipped the bike to me here in Oklahoma. I put it in storage where it's been until I took it out to make it run again last autumn. Pirate (my friend) never mentioned any braking problems.
Other than the extremely dirty condition, there was nothing remarkable except for the following:
1. There were two wave washers installed.
2. The snap ring was improperly installed.
3. A piece came out that looked like a push pin (An item our American women call a "straight pin," commonly used for sewing.) except it was much thinner and had a round ball on one end with a sharp point on the other.
4. The smaller of the two holes on the top of the master cylinder appears to not have been drilled all the way through. I can see (through the large hole) the spring/piston assembly move when I push the rod but not when I look through the small hole.
The number cast into the bracket is 3715-223C. Also cast below the number are two large upper-case letters: "AH."
I have carefully adjusted the unit according to Lockheed's instructions (sent to me by L.A.B.) Unlike the front master cylinder, no air passes through the small hole after this adjustment. Even if I operate the push rod, no air will flow when I blow through the end where the banjo connects.
I'm beginning to think that this master cylinder was manufactured when a certain employee was having a bad day.
Knowing Pirate, he could have driven the bike with no rear brake, accepting it's lack as merely a part of his difficulties with life.
Should I drill the hole all the way through?
Should I bite the bullet, shell out another $220 and buy a new master cylinder?
Should I do the first and, if necessary, do the second choice?
I'm looking forward to working on the Norton with its mechanical brakes!
Al
Thanks for all the suggestions, L.A.B. I intend take the unit apart and use them as soon as I understand other problems. First some history on the bike.
The company I worked for in Germany sold the bike to an American serviceman. On his ride home, a car entered the road in front of him, causing him to have to brake hard and take evasive action. No accident occurred
The leading edge of the rear wheel went to the right in the swinging arm and hit the master cylinder, causing a loss of fluid. I'm not sure how that happened.
Meriden sent us a complete new assembly including rear swinging arm, tire, caliper, master cylinder, etc., all installed. They also discounted the bike because the customer insisted on a new motorcycle.
I bought the bike but resold it to another employee who eventually didn't pay me for it. I had moved back to the states in the meantime so he shipped the bike to me here in Oklahoma. I put it in storage where it's been until I took it out to make it run again last autumn. Pirate (my friend) never mentioned any braking problems.
Other than the extremely dirty condition, there was nothing remarkable except for the following:
1. There were two wave washers installed.
2. The snap ring was improperly installed.
3. A piece came out that looked like a push pin (An item our American women call a "straight pin," commonly used for sewing.) except it was much thinner and had a round ball on one end with a sharp point on the other.
4. The smaller of the two holes on the top of the master cylinder appears to not have been drilled all the way through. I can see (through the large hole) the spring/piston assembly move when I push the rod but not when I look through the small hole.
The number cast into the bracket is 3715-223C. Also cast below the number are two large upper-case letters: "AH."
I have carefully adjusted the unit according to Lockheed's instructions (sent to me by L.A.B.) Unlike the front master cylinder, no air passes through the small hole after this adjustment. Even if I operate the push rod, no air will flow when I blow through the end where the banjo connects.
I'm beginning to think that this master cylinder was manufactured when a certain employee was having a bad day.
Knowing Pirate, he could have driven the bike with no rear brake, accepting it's lack as merely a part of his difficulties with life.
Should I drill the hole all the way through?
Should I bite the bullet, shell out another $220 and buy a new master cylinder?
Should I do the first and, if necessary, do the second choice?
I'm looking forward to working on the Norton with its mechanical brakes!
Al
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- Nov 20, 2004
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- 20,082
Re: Rear Master Cylinder
Sounds more like a dressmaking pin, I think? But whatever it is, I don't think it should be there!
The smaller of the two holes is about 1/8" diameter but only the outer part it should not be drilled all the way through to the cylinder bore at that diameter as the 1/8" dia. part is a counterbore, so don't mistake it for the actual bleed hole which is at the bottom of it, and I'd guess is about 20-25 thou diameter, and if that becomes blocked it can look as if it isn't actually there at all?
If it is a blockage then a piece of fine stiff wire (a single wire from a wire brush?) can be used to clear it.
3715-223C is the number I would expect to fiund on the rear master cylinder casting. Could AH actually be "8 H" with the H squashed? Which could be the ID of the casting manufacturer?
Try unscrewing the barrel assembly one full turn? If that doesn't do it, then either the tiny hole is blocked or it isn't drilled, or the hole in the check valve is missing?
Or somebody has dismantled it before?
Provided there's no damage or corrosion to the bore, and the piston is OK, then I see no reason not to re-use it, provided you get the bleed hole problem sorted?
In the UK the barrels only, or barrel assemblies can be bought considerably cheaper than the complete units, as it is only the barrel parts that really wear out or corrode and need to be replaced. And stainless steel barrel assemblies are available.
Tulsaalva said:
Sounds more like a dressmaking pin, I think? But whatever it is, I don't think it should be there!
Tulsaalva said:
The smaller of the two holes is about 1/8" diameter but only the outer part it should not be drilled all the way through to the cylinder bore at that diameter as the 1/8" dia. part is a counterbore, so don't mistake it for the actual bleed hole which is at the bottom of it, and I'd guess is about 20-25 thou diameter, and if that becomes blocked it can look as if it isn't actually there at all?
If it is a blockage then a piece of fine stiff wire (a single wire from a wire brush?) can be used to clear it.
Tulsaalva said:
3715-223C is the number I would expect to fiund on the rear master cylinder casting. Could AH actually be "8 H" with the H squashed? Which could be the ID of the casting manufacturer?
Tulsaalva said:
Try unscrewing the barrel assembly one full turn? If that doesn't do it, then either the tiny hole is blocked or it isn't drilled, or the hole in the check valve is missing?
Tulsaalva said:
Or somebody has dismantled it before?
Tulsaalva said:
Provided there's no damage or corrosion to the bore, and the piston is OK, then I see no reason not to re-use it, provided you get the bleed hole problem sorted?
In the UK the barrels only, or barrel assemblies can be bought considerably cheaper than the complete units, as it is only the barrel parts that really wear out or corrode and need to be replaced. And stainless steel barrel assemblies are available.