Lockheed CP2696 Brake Retrofit

OK, maybe someone out there can help me. I picked up an 1976 850 interstate electric start. The bike came with a brand new Lockheed CP2696 -101C Brake caliper and mounting bracket. I decided to replace the stock Lockheed caliper with the CP2696. The master cylinder is a Nissin S13 1/2. Got everything together and mounted. No leaks. Pumped tons of brake fluid through the system both ways but can't get the master cylinder to take up. If I pump it a couple of times the brakes take up but 10 seconds later nothing the lever goes all the way down. I don't think there is any air in the caliper. The brake worked fine with the stock caliper. I'm stumped. Any help would be appreciated.

Cheers,
Larry

Seals are old and dried out and letting in air ? Was there fluid in there when purchased or was this dry ?

Torontonian said:

Seals are old and dried out and letting in air ? Was there fluid in there when purchased or was this dry ?

Click to expand...

+1

There was fluid in the system with the original caliper and the system worked. Now during the retrofit all the fluid ran out of the system but not so long to allow any seals to dry out.

These tiny motorcycle mastercylinders and calipers can be tough to bleed. Best is to attach tight fitting tubing to the bleeder on the caliper then use a syringe to bleed the system backwards by pushing the fluid in at the bottom end(caliper). The air bubbles in the sytem are happier rising than falling. If there are two bleeders on the caliper you will need to do one then the other.

Glen

Glen

The brake hose must not go up above the level of fluid in the reservoir or air can get in. I don't know if that is your problem but I have had this happen before.

Nigel

lar1949 said:

OK, maybe someone out there can help me. I picked up an 1976 850 interstate electric start. The bike came with a brand new Lockheed CP2696 -101C Brake caliper and mounting bracket. I decided to replace the stock Lockheed caliper with the CP2696. The master cylinder is a Nissin S13 1/2. Got everything together and mounted. No leaks. Pumped tons of brake fluid through the system both ways but can't get the master cylinder to take up. If I pump it a couple of times the brakes take up but 10 seconds later nothing the lever goes all the way down. I don't think there is any air in the caliper. The brake worked fine with the stock caliper. I'm stumped. Any help would be appreciated.

Cheers,
Larry

Click to expand...

OK, so does the lever go down while you are holding it after pumping 10 times (leaking master cylinder) or does the handle go down after pumping ten times, releasing, waiting ten seconds and trying the lever again (air in line, misalignment of caliper to disk, uneven pad wear, caliper seals hanging). Makes a big difference. When you pump the brakes up are they firm?

Check for excessive movement or odd movement down at the caliper. If things are tight there then could be air or leak down of the master cylinder. When bleeding, often times it is helpful to take the master or caliper off and move around to get bubbles out of nooks, crannies and bends.

Like a Thomas's English Muffin'. Air is getting in somewhere ,start again...

Hi
I have a race bike with a Grimeca mastercylinder & it is a pig to bleed. Advice given is to pump the lever then cable tie it to the handlebar. Leave overnight. It allows the trapped air to find its way into the reservoir.

Chris

Chris said:

Hi
I have a race bike with a Grimeca mastercylinder & it is a pig to bleed. Advice given is to pump the lever then cable tie it to the handlebar. Leave overnight. It allows the trapped air to find its way into the reservoir.

Chris

Click to expand...

+1

I fitted a banjo bolt that has a bleed nipple in it. You can bleed the air directly out of the master cylinder. I think ( although it was many years ago) I bought it from a Honda dealer. You'd need to check the thread is correct for a Lockheed.

I believe I've got it. Here's what I did. First I filled the caliper by pumping fluid down from the master cylinder and out the top bleeder. Then I pushed fluid backwards with a syringe through the caliper into the master cylinder to make sure there was no air trapped in the master cylinder. The CP2696 that I have has two bleeders at each end of the caliper. I then removed the caliper leaving the hose connected and turned it so the bottom bleeder was pointing up and bled a dollop of air out. I then turned the caliper so the other bleeder was pointing up and bled that one. I did this a couple of times just to make sure all air was out of the caliper. I might mention that I inserted a piece of 1/4" aluminum plate between the brake pads to make sure the pistons didn't move while bleeding.

I remounted the caliper, topped up the master cylinder and now it feels like a brake should. Many, many thanks to all those out there that helped.

Cheers,
Larry

Power bleed. No problems. Very quick. Requires a modified master cylinder cap and a pressure source, such as a small weed sprayer. Works for ABS, as well as conventional systems. Never tried backwards pressure bleeding, from caliper bleed nipple up, but it makes sense.

Actually aircraft brakes are bled in this manner from the caliper to the master cylinder.

Hi

Just to add to Pommie Johns post
I use hel banjos one because it has a brake light switch but I forgot I also have the bleed one!!! Not used it yet!!!!!

Chris