Roadster Tank Rubber Removal

nomadwarmachine · Sep 18, 2019

In the process of refreshing all of the 45-year old rubber on the bike and I have a split rear tank rubber on my 1974 Commando Roadster. The rubber cushion is split and the stud is stuck in the tank. I want to be very careful NOT to bend or otherwise damage the (original) tank as I remove, and am asking for advice.

Looks like the bottom of the rubber flush with the tank is a washer that I can grab with a pair of pliers. Should I give it a good yank or soak with PB Blaster, cut away the rubber and try to get a pair of pliers on the stud -- is there anything to grab?

T(h)anks!!

nomadwarmachine · Sep 18, 2019

Note that the rear rubber appears to be identical to the exhaust mount rubbers. Cannot tell from the Old Britts diagrams whether that is correct or a retrofit. Replace as is?

Nortoniggy · Sep 19, 2019

The original mounting was a plain threaded stud with a selection of large rubber washers. Some people have replaced that arrangement with the exhaust mounting type rubbers. It sounds like that is your situation. You just need to be careful unscrewing it. Soaking it in something first is probably a good idea.

Ian

nomadwarmachine · Sep 19, 2019

Ian, looks like you are correct about the replacement with the exhaust rubber. Will leave both to soak until the weekend and have another go. Given that it is a painted surface, heat does not seem to be an option. The rubber is presently torn and the stud is really stuck!

htown16 · Sep 19, 2019

Use a pair of vise grips. I'd replace them with the correct stud and stack of rubber washers so it doesn't happen again. Using the cotton reels seems to work on the back of the tank but not on the front.

drp · Sep 19, 2019

I'd probably double nut it, lock the nuts together and use a box wrench. I have seen people use something called CRC freeze and they spray the stud and then break it loose. When you get it out coat the threads with never seize
Dave

nomadwarmachine · Sep 19, 2019

drp said:
I'd probably double nut it, lock the nuts together and use a box wrench. I have seen people use something called CRC freeze and they spray the stud and then break it loose. When you get it out coat the threads with never seize
Dave

Dave, the double-nut approach worked perfectly on the front stud, but the rubber buffer ripped in half (imagine a hamburger bun with a separate toothpick sticking out each end and nothing through the middle) so there is nothing to thread. Looks like vise grips and PB blaster are the way to go. May even try to cut parallel sections off the washer so that I have more surface to grip.

HTown16, these buffers are on the back of the tank. Do you think it better to replace with new buffers (coated in anti-seize) or would you still go to the studs/washers?

Tornado · Sep 19, 2019

I 've got an exhaust iso bushing that has split in half. One side has nearly all rubber removed and I can report there is a hex head sitting against the steel washer. So you may be able to clear away the rubber on your stuck bushing with a dremel or otherwise then get a proper tool on the hex to undo it.

You could try heating with a heat gun to help break free if pb blaster etc fails. Safer than propane torch on the paint.

nomadwarmachine · Sep 19, 2019

Tornado said:
I 've got an exhaust iso bushing that has split in half. One side has nearly all rubber removed and I can report there is a hex head sitting against the steel washer. So you may be able to clear away the rubber on your stuck bushing with a dremel or otherwise then get a proper tool on the hex to undo it.

You could try heating with a heat gun to help break free if pb blaster etc fails. Safer than propane torch on the paint.

This is excellent. Thank you. I love this forum.

cliffa · Sep 19, 2019

Tornado said:
I 've got an exhaust iso bushing that has split in half. One side has nearly all rubber removed and I can report there is a hex head sitting against the steel washer. So you may be able to clear away the rubber on your stuck bushing with a dremel or otherwise then get a proper tool on the hex to undo it.

You could try heating with a heat gun to help break free if pb blaster etc fails. Safer than propane torch on the paint.

Yep, I have a broken one as well, and can see a hex in the end.

If using a disc cutoff tool or any form of heating equipment bear in mind this is a fuel tank, which are potentially as dangerous when empty.

FYI : 50/50 acetone/ATF is reputed to be the best penetrating solution.

Cheers,

cliffa.

htown16 · Sep 19, 2019

The buffers on the back of the tank have held up in my experience. It may be because the strap holds tank fairly securely so they don't flex to much. Even if one were to fail the tank wouldn't move much due to the strap being held by the other side. If you were to put them on the front though a failure could see the tank lift.

Tornado · Sep 19, 2019

Here's a shot of the split bushing inards

I guess the take home from this is to be extra careful when torquing these bushing to hold the piece by the washer edge and not the rubber or far side stud.

nomadwarmachine · Sep 19, 2019

Torontonian · Sep 19, 2019

Protecting the paint from heat gun blisterings as well as gasoline fumes exploding are first priority. I'd get brutal with needle nose vise grips after spraying a penetrate onto the studs and letting it sit for a bit. Wrap the tank in a towel too.

cyclegeezer · Sep 20, 2019

It's counter intuitive, but sometimes after getting the penetrating oil in, trying to first tighten the fastener then loosening it will help break the corrosion.

lazyeye6 · Sep 20, 2019

cliffa said:
Yep, I have a broken one as well, and can see a hex in the end.

If using a disc cutoff tool or any form of heating equipment bear in mind this is a fuel tank, which are potentially as dangerous when empty.

FYI : 50/50 acetone/ATF is reputed to be the best penetrating solution.

Cheers,

cliffa.

I had read about and tried the 50\50 acetone/ATF (type F) mixture as the "best" penetrating solution. I found that it was
like mixing oil and water. The two fluids immediately separated. Maybe I was doing it wrong? I found Kroil to be the
ultimate commercial penetrating fluid. http://www.kanolabs.com/msn/?msclkid=1ef828f609871a279a267572f0cf51f3

Tornado · Sep 20, 2019

Since the owner is concerned with protecting paint even on the unseen underside, using acetone, which is a strong solvent, needs to be done carefully

cliffa · Sep 20, 2019

Tornado said:
Since the owner is concerned with protecting paint even on the unseen underside, using acetone, which is a strong solvent, needs to be done carefully

Agreed.

nomadwarmachine · Sep 23, 2019

Update: The stud is out. Soaked with PB blaster and applied steady torque with a pair of needle-nosed pliers. The second buffer looks fine and will be left alone. I will just replace the one that I removed with a new buffer.

Thanks to all!

Roadster Tank Rubber Removal

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