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Brake Caliper Rebuilds

  • Thread starter Thread starter DevanJones
  • Start date Start date
D

DevanJones

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I tried the advanced search but I couldn't find much in terms of a write up or anything. Where can I get a rebuild kit and is there anything I should know going into this? I need to rebuild my front calipers.

Yesterday I replaced my pads and bled the brakes (first time but I used my book and it seemed to go fine). Brakes were working fine at first but they engaged and wouldn't disengage after riding for a bit. I bled them and that relieved pressure but it would build back up. So I tried it again. I tried to bleed my brakes but they continue to gradually tighten up. So I started over.

Pulled the calipers off the bike, loosened the valve up, pushed the piston side brake pad into the piston (compressing it) and then tightened the valve up. Did the same on the other front caliper. Put the bike on the center stand and started spinning the front wheel and braking. Each time I squeezed the brake would engage but it wouldn't quite fully disengage each time so it became progressively harder and harder to spin the tire.

I would say something here is wrong since it seems to be both calipers up front and figured I might as well just rebuild them.
 
All you need to do is break them down FULLY.

Clean the crud out ofthe grooves the piston seals set in and off the seals themselves. I just scrape the seals with a fingernail and the crud comes off.

Clean the carrier pins for the pads as well.

Basically what youll find is that the crud built up inside the seal grooves is taking up the space the seals need to set back in there right. This crowding for space has to have an effect somewhere...and that place is on the pistons. the seals are gradually getting squeezed tighter and tighter around the pistons and they dont relax when you let off the brake lever..follow me?
 
I didn't realize there was a guide to rebuilding calipers on BC's website. Thanks, guys.
 
DevanJones said:
.....

...... Brakes were working fine at first but they engaged and wouldn't disengage after riding for a bit. I bled them and that relieved pressure but it would build back up. So I tried it again. I tried to bleed my brakes but they continue to gradually tighten up. So I started over.

Pulled the calipers off the bike, loosened the valve up, pushed the piston side brake pad into the piston (compressing it) and then tightened the valve up. Did the same on the other front caliper. Put the bike on the center stand and started spinning the front wheel and braking. Each time I squeezed the brake would engage but it wouldn't quite fully disengage each time so it became progressively harder and harder to spin the tire.

I would say something here is wrong since it seems to be both calipers up front and figured I might as well just rebuild them.
Click to expand...

It sounds like there's an issue with the Master cylinder on the handlebars. Especially,I think you should find identify, find and clear the tiny "return hole" in the Master cylinder ....it often gets plugged.
 
It only takes one caliper to bind to cause the front wheel to drag, it's better to rebuild both than find and fix the one. There's also the master cylinder theorem which is what I had happen on my rear brakes as the master cylinder piston would release after application due to all the crud that built up.

The easy way to determine which part is the culprit - master cylinder or caliper - is to get your to bind and carefully without disturbing the caliper open the bleed screw, if your wheel now spins free as can be then your problem is with the master cylinder. If it does not spin freely after this then your caliper is binding.
 
DevanJones said:
I tried the advanced search but I couldn't find much in terms of a write up or anything. Where can I get a rebuild kit and is there anything I should know going into this? I need to rebuild my front calipers.
Click to expand...


OEM parts are available through a multitude of on-line sources, or just go to your local Suzuki motorcycle dealership. Try a google search, or search here for the forum favorites. I like Bike Bandit and Boulevard Suzuki. Google those terms and start reading.

You should order new OEM caliper seals, and new seals for your master cylinder. You may be able to reuse the seals after cleaning so consider that if money is an issue.

Fully break down both the calipers and master cylinder and scrub them clean. Look for pitting in the master cylinder bore before assuming it can be rebuilt. Grease the caliper sliding pins with high temperature caliper grease with moly. Your local auto parts store should have this stuff.

It's also critical to replace your brake lines, which are all full of scally crap after 30+ years of use. There are tons of different threads on this subject too so try an advanced search, using Titles Only, for "brake lines".

BTW, if you can't find info such as detailed above using the search feature here, you ain't trying.:p

Good luck
 
Gorminrider said:
It sounds like there's an issue with the Master cylinder on the handlebars. Especially,I think you should find identify, find and clear the tiny "return hole" in the Master cylinder ....it often gets plugged.
Click to expand...

I concur with this . However - if you want to di it right then do BOTH the calipers and master cylinder . That way you KNOW it is ready to go for a long time......
 
And replace the original brakes lines

Are you ever going to follow the advise given to you here and at PNW Riders?

Note: Devan has been posting his problem, getting good advise on the MC and continuing to ride the bike without following the advise, He got stranded the other day with a seixed front brake
 
Big T said:
And replace the original brakes lines

Are you ever going to follow the advise given to you here and at PNW Riders?

Note: Devan has been posting his problem, getting good advise on the MC and continuing to ride the bike without following the advise, He got stranded the other day with a seixed front brake
Click to expand...

I haven't ridden my bike since I learned there was a problem with the brakes. In fact, the reason I made this post here and at PNWRiders was because my brakes were seized. I rode it home on backroads and it since been parked in my garage. I rode it once around my neighborhood after a thorough bleeding to see if that had fixed the problem. After .2 miles it was clear I hadn't fixed the problem and returned home. I am unsure what advice I haven't followed or attempted to follow.
 
I attempted to rebuild the break calipers this evening, but I couldn't even get one of the pistons out of the caliper. The piston that was removed had a little scoring as well as some rust in the piston housing. I'm taking the calipers to a shop in the morning to get a professional opinion. I'm about to go and work on the master cylinder.
 
DevanJones said:
I attempted to rebuild the break calipers this evening, but I couldn't even get one of the pistons out of the caliper. The piston that was removed had a little scoring as well as some rust in the piston housing. I'm taking the calipers to a shop in the morning to get a professional opinion. I'm about to go and work on the master cylinder.
Click to expand...

The calipers themselves are usually OK - just make sure that the groove where the seal sits is cleaned properly. Clean out the opening for the piston in the caliper - some marks in there do not make the caliper unusable, unless they are around the groove where the seal sits.

If the shiny surfaces of the pistons are scored lightly, careful polishing with fine wet-and-dry paper should sort it out. However, heavy scoring or rust pitting will require replacement of the pistons, as the seals will never be able to seal properly. Get either OEM pistons or stainless steel replacements. Use OEM seals.
 
Okay. The pistons are scored and I would guess probably enough to make it not worth attempting to save. And I cleaned out the master cylinder. It was filthy under the reservoir. I cleaned it all out, vacuumed the scrapings, scraped some more, vacuumed again and then cleared the little holes in the bottom of the reservoir before reinstalling. Tomorrow I'll find out about the pistons, and then I'm going to order what I need, which is stainless steel lines, a master cylinder o-ring, some little seals that sit around the piston, and potentially pistons. There goes my spending money for the next couple months.
 
Yeah, new parts for brakes aren't cheap, but once it's done, they're good for another 30 years. (As long as you remember to change the fluid at least every other season!)
 
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More than I want to spend but I want to ride and I want to be done with working on my brakes for the foreseeable future so I bit that stupid bullet.
 
You should also overhaul the rear m/cylinder and caliper and replace the brake line - remember it will look the same inside as the front!

You should always bear in mind that brakes are safety critical items - and ask yourself how much your life is worth, when thinking you can maybe skimp on something as far as brakes are concerned.
 
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