FZJ80 Rear break leaking break fluid

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dansawyer

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The right rear break caliper is leaking break fluid. Is this a symptom of a worn pad or is it likely more serious?
Thank you in advance for you support in diagnosing this. Dan
 
Rusty Marlin

Rusty Marlin

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Worn pads won't cause a leak.
Where is the leak coming from?
Around the banjo bolt or from behind the pad?
 
Irish Reiver

Irish Reiver

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It will depend on where it is leaking from (hose connector, bleed nipple, piston). If it is the piston then you likely have a worn or damaged seal. It is possible that worn pads have allowed a corroded piston to let brake fluid escape past the seal however replacing the pads may not fix that if the seal was damaged. Best to pull the caliper and have a good look. Remove the piston and check for corrosion. If all is good, a rebuild kit is fairly cheap.
 
flintknapper

flintknapper

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RC0

RC3

RC9
RC4
 
flintknapper

flintknapper

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👆🏽 This is really not as hard of a job as it looks. Most difficult part is usually getting the piston out.

Piston was no problem....a number of ways to do that easily.

Cleaning the parts was the most work for me and I don't even live in the rust belt.

But I believe strongly that brake parts should be nice and clean before being reassembled/rebuilt.
 
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dansawyer

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Got it. Thanks. The kit is on order.
 
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clx16

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No need to disconnect the brake line. just pop the piston out with the peddle, then just rebuild, then clean off the brake fluid, mount and bleed. bleed a lot just because it is a good time to do a flush and only takes a few extra minutes. Brake fluid should be clear, not green or yellow or white etc.
 
flintknapper

flintknapper

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No need to disconnect the brake line. just pop the piston out with the peddle, then just rebuild, then clean off the brake fluid, mount and bleed.

Sounds easy but I can tell you from having done it, you'll want to have the caliper 'in hand'. Getting the boot over the piston can be tricky....not to mention you 'should' thoroughly clean everything....NOT just throw some parts at to get it over with.

Take a little pride in your work and do it right.
 
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clx16

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True you need something to hold the caliper so it isn't hanging, i have a 6x6x24 inch piece of wood and a drain pan on top of it. I clean the caliper before ripping it open. If your pistons are still good. I keep a spare 1 or 2 new ones just in case i find the old ones pitted or otherwise damaged. I slide the boot over the piston before trying to slide the piston in to the caliper. putting the boot on the caliper first has never worked for me. Having spare parts make the job a lot faster. Once you get the new seal in then slide the boot down low on the piston and then the boot in the groove and slip the piston in. let the bleeder out a little and repeat for the other piston. then clean the brake fluid off the whole thing and remount. put pads in and bleed it out.

This year already I have rebuilt two front sequoia calipers, 2 front calipers to a 79 pickup, 3 rear 80 series calipers and I will tell you, if there is any rust around that seal and inside of the boot, you have to stop the rust or you will be back in again soon. If it has gotten too bad, replace the caliper. You can rebuild on the trail to stop sticking but it won't last so be prepared.
 
jonheld

jonheld

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Indeed. I typically just remove the pads, remount the caliper, and stomp the brake pedal tho. Pops the pistons out to the rotor without shooting them across the garage!
The rear caliper piston is captured by the housing. It won't shoot out if you're careful.
For the fronts I use a wood spacer that also makes quick work of getting all 4 pistons out.
 
flintknapper

flintknapper

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True you need something to hold the caliper so it isn't hanging, i have a 6x6x24 inch piece of wood and a drain pan on top of it. I clean the caliper before ripping it open. If your pistons are still good. I keep a spare 1 or 2 new ones just in case i find the old ones pitted or otherwise damaged. I slide the boot over the piston before trying to slide the piston in to the caliper. putting the boot on the caliper first has never worked for me. Having spare parts make the job a lot faster. Once you get the new seal in then slide the boot down low on the piston and then the boot in the groove and slip the piston in. let the bleeder out a little and repeat for the other piston. then clean the brake fluid off the whole thing and remount. put pads in and bleed it out.

This year already I have rebuilt two front sequoia calipers, 2 front calipers to a 79 pickup, 3 rear 80 series calipers and I will tell you, if there is any rust around that seal and inside of the boot, you have to stop the rust or you will be back in again soon. If it has gotten too bad, replace the caliper. You can rebuild on the trail to stop sticking but it won't last so be prepared.

You can also block the piston, then use a regulated amount of compressed air and a rubber tipped blowgun to 'inflate' the boot. Use a dull pick to go around the lip of the boot (fit it to the piston) for a very easy installation.

And you are spot on about the rust, No Bueno! 👍
 
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ucmikej

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I too am doing this job and came across a video that might offer some insight. The video installs the pistons as @clx16 Said.

 

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