81 xj 650 Stuck front brake caliper...WD-40???Diesel fuel???

I have heard of many different ways to unstick these calipers. But, I just wanted some input on the best way there is to do it without causing any damage to the piston or caliper itself.

 

If you are unable to free them up by simply disassembling, try compressed air, ensuring you place a wooden block in the caliper harp to catch the piston and keep it from becoming a missile. If compressed air fails, refill and bleed the brake system, then use hydralic pressure to force it free. Failing that, you need to get a new piston and/or caliper. Best of luck, this can be a "sticky" situation.

 

watch your fingers when you put the air on that caliper.
Those pistons can bite REALLY hard!

 

Note that a co-worker found the parts for a caliper rebuild online for dirt cheap... way way cheaper than at a dealership and it's an easy rebuild project.

 

Re: 81 xj 650 Stuck front brake caliper...WD-40???Diesel fue

My caliper was REALLY stuck, also. I heated up the entire unit in an oven for about 20 minutes (or you can use a small propane torch on the caliper body). I then used some crushed ice chips from my frig and stuck them down in the piston and let it sit for about 5 minutes, dumping the melted ice/water and refilling with ice as needed (of course, all of this after a very liberal soaking of WD40 around the outside edges of the piston). THEN hit it with compressed air (120 pounds worth). And out she came.......

 

Re: 81 xj 650 Stuck front brake caliper...WD-40???Diesel fue

And that ain't no lie! It takes right at 120 lbs to move these things. I tried with 85 then 100 with no results. Finally at 115 it broke loose and moved, but verrryy slooooowwly. And please keep your fingers out of the way! I didn't do it but a friend of mine did and it hurt like heck. I also used some brake parts cleaner in a spray can that I think was required for my success. I sprayed it on the visible part of the piston and then cleaned with a shop rag. Pushed the piston down into the caliper to free it and then applied the air. Used an air gun with a rubber tip for this. The rubber tip is crucial. Without it you won't get a seal.

 

thanks every1 for the info.....I'll have to take it to work with me and use thei air compressor

 

Re: 81 xj 650 Stuck front brake caliper...WD-40???Diesel fue

Really stuck pistons can be 'popped' out .. safely.. and rather easily..by using a Grease gun.. Cobble up a grease fitting to screw into the brake fluid line intake hole on the caliper.. attach grease gun then happily pump away. Soak in Varsol afterwards to wash out the grease mess.

 

And please keep your fingers out of the way! I didn't do it but a friend of mine did and it hurt like heck.

Oh I dont know... I din't feel a thing!

 

would a conversion to duel front brakes be much of a hassel ?

 

Re: 81 xj 650 Stuck front brake caliper...WD-40???Diesel fue

define "hassle"............. :lol:

 

more work than its worth. Will it make a noticable difference

 

My XJ700 has dual front disc brakes and it does stop very well!

Provided you could find a suitable donar bike the modification shouldn't be too big a deal..

If you are running around trying to find the components or trying to design and build the brake system from scratch I'd rate it a 10 on the hardness scale.

 

Re: 81 xj 650 Stuck front brake caliper...WD-40???Diesel fue

Dunno.. I do know that the dual disc setup stops.. eventually. Yes the system is healthy and the pads are of v good quality... it stops every bit as well as it did when brand new.. BUT.. ride a 'modern' moto like an R6 or R1 and you may scare yrself silly.
Brakes on those are two fingers only.. v gently squeeze and that lifts the rear wheel, as in up off the ground..not fun the first time, let me tell you
On my old Yama it's : grab a handfull and squeeze hard for a LOT less braking. Now I'm really spoiled by the experience and seriously wonder about the actual braking capabilities of these 20+ yr old Bikes...
Gawd help us if we really do need to stop.. right Now.

 

Duals are a nice up-grade provide the parts fall easily to hand Shaun. I wouldn't blow more than $200 for everything including the new lines and rebuild kits.

 

Re: 81 xj 650 Stuck front brake caliper...WD-40???Diesel fue

When I find a piston stuck in the caliper I remove the bleeder screw and replace it with a grease zerk. I pump it full of grease with a grease gun. I get 10,000 PSI of pressure and I don't worry about removing a finger. Works every time.

D

 

but there's no suspense, no excitement and no explosion. what fun is that

 

....and no missing fingers. Sorry

 

Oh polock... no fun at all unless there's a hole in the ceiling when you're done :lol: