problematic brakes

[CJ]

Does anyone know the telltale signs when one of the brake pistons gets stuck in the caliper? I've had ongoing problems with brakes over the past few months and I reckon this might be the problem. Braking hard isn't a problem, but coming to a stop slowly is (accompanied by an annoying screeching sound). I also notice that when taking the foot off the brake pedal when at the lights while moving off results in a clunking sound on the LHS. I've convinced one of the pots is stuck but I'm unsure of how this is normally manifested. Any takers?


Ciaran

[CJ]

Right, one of the pistons is screwed, I tried lubing it up without joy. When you depress the brake pedal, one pot comes out but not the other, see below



I can get the other pot out by clamping up the working one and again depressing the brake pedel but both won't operate at once:



I assume this can't be fixed and I need a new caliper, can anyone confirm?

Ciaran

[keville]

Ciaran,

Its probably the seals that went on the piston so the build up of brake dust may have locked up the piston thats not working(did you notice if the seals were gone)
Im not 100% sure but I think you can get kits to reseal the pistons I remember a couple of years ago a guy got them for me for a toyota twin cam,but i haven't a clue if you can get them for the fto....

Keville

[CJ]

The seals on the pistons *look* ok but I think you're right as regards brake dust clogging them up. I've mailed U-save in the UK for price on a used caliper as I can't see any other way of sorting the problem. As far as I can see, theres no way to strip down the caliper

Ciaran

[Dean]

As of friday I am getting a squealing from the right front wheel as well. Happens until I make a sudden stop and press the brake hard, then it goes away until I leave the car for an hour or so, comes back then.
I am guessing simple fix like pad change, but cant be sure.

[soc]

The seals on the pistons *look* ok but I think you're right as regards brake dust clogging them up. I've mailed U-save in the UK for price on a used caliper as I can't see any other way of sorting the problem. As far as I can see, theres no way to strip down the caliper

Ciaran

kempy's are pretty cheap for used calipers.

[steelroe]

Ciaran,

You can get seal repair kits.
The piston should pull straight of the caliper. If you take it out and clean it with rust off or something similar. Remove the seal from the piston carefully.
There is a section on brake caliper maintenance in the FTO manuals.

Is there enough fluid in the reservoir?

Rory

[steelroe]

Ciaran,

Are you saying that when you clamp one pot and apply the brake the other one comes out?


Rory

[CJ]

Ciaran,

You can get seal repair kits.
The piston should pull straight of the caliper. If you take it out and clean it with rust off or something similar. Remove the seal from the piston carefully.
There is a section on brake caliper maintenance in the FTO manuals.

Is there enough fluid in the reservoir?

Rory

Crap, I just ordered a new caliper from Kempys in NZ better cancel it for the mo. When I clamp up either of the two pistons, the other one will pop out when the brake is depressed, when unclamped only one of the comes out of the caliper. They seem pretty tightly stuck, any hints for getting them out of there? The resevoir is nearly full btw.

Cheers

Ciaran

[soc]

Crap, I just ordered a new caliper from Kempys in NZ

Ciaran

How much were you quoted for the recon caliper from kempys?

[CJ]

How much were you quoted for the recon caliper from kempys?

NZ$106 for one used caliper and $110 shipping all in, it was €113 or so....

[soc]

How much were you quoted for the recon caliper from kempys?

NZ$106 for one used caliper and $110 shipping all in, it was €113 or so....

damn shipping is a lot - i was thinking of upgrading the calipers on my GR to the twin pots from the GPX... suppose 200 euro aint bad for 2 calipers.

[CJ]

For anyone thats interested, heres 2 links to some good articles about disassembling brake calipers:

http://www.head2head.free-online.co.uk/ ... aliper.htm
http://www.geocities.com/MotorCity/Down ... build.html

I'll let you know how I get on.

Ciaran

[CJ]

Right, I've made matters worse I dissasembled the caliper\piston, all looked OK so put it back together. While I was in the process, I changed the brake fluid and bled all of the old fluid out of the system making sure that there was always fluid in the resevoir. Now, when I pump the brake pedal, its only stays firm for a few seconds, as a result, stopping distance has increased a fair bit. Any ideas folks?

Ciaran

[steelroe]

You still have cair in the system.

Rory

[keville]

ha-ha!

Still a bit shakey from last night but i think Rory meant you still have air in the system

Keville

[CJ]

You still have cair in the system.

Rory

Thats what I thought as well, all sorted now thanks to the correct bleeding technique, theres a lot to be said for RTFM

However, I still have the original problem! Might leave it to the experts at this stage...

CJ

[keville]

Ciaran the brakes are pretty good on my gr but i was wondering do the calipers for the gpx bolt on to the gr or is there adjustments to be made

Keville

[CJ]

Ciaran the brakes are pretty good on my gr but i was wondering do the calipers for the gpx bolt on to the gr or is there adjustments to be made

Keville

GPX calipers will bolt straight onto a GR but you'll also have to change the disks and the pads to suit. In addition to that you will also have to cut away some of the heat shield to accomadate the new disks.
GS and GR calipers share the same single pot units while the GPX has twin pots units. GPX disks have a larger diameter but I don't have dimensions to hand.

Ciaran

[keville]

Cheers Ciaran I may have a go at this over the next couple of weeks

Keville

[soc]

Cheers Ciaran I may have a go at this over the next couple of weeks

Keville

AFAIK, it's a pretty straight forward swop and it shouldn't be any different to changind disks pads

[keville]

Thanks Shane,

All I have to do now is locate the calipers as im goin to buy the disks

Keville

[soc]

You still have cair in the system.

Rory

Thats what I thought as well, all sorted now thanks to the correct bleeding technique, theres a lot to be said for RTFM

However, I still have the original problem! Might leave it to the experts at this stage...

CJ

Hey Ciaran,

I'm thinking of changing my brake fluid but having never done it before I want to make sure I do it right. I've had a quick look in the manual and I know that you have to do it in sequence - passenger side rear, drivers side front, drivers side rear, passenger side front - but I'm not 100% sure on the the actual bleeding..... do I need someone to help me, i.e. to press the brake pedal when actually bleeding each brake line? And how do I prevent the resevoir from running empty - do I just top up the resevoir with new fluid - but will the new fluid not mix with the old fluid? Now I've just confused myself .......

[CJ]

[I'm thinking of changing my brake fluid but having never done it before I want to make sure I do it right. I've had a quick look in the manual and I know that you have to do it in sequence - passenger side rear, drivers side front, drivers side rear, passenger side front

You've got the sequence right anyway Shane. This is the way I did it:

1. From 2 drain points, (one front and rear), drain off as much of the old fluid without running the resevoir dry.
2. Fill the reservoir up with new fluid and repeat the same process, this time, from the other two drain points.
3. Fill the resevoir up again and bleed the brakes in the correct sequence.

Make sure you have 2 Lites of fluid just in case, there will be some wastage from the bleeding process. The important part is not to let the resevoir run dry so check if often during the process. When you've finished, pump the brake pedal to get the pressure back up again. If the pressure drops after a few seconds, theres still air in the system which means bleedin the system again.

Ciaran

[soc]

[I'm thinking of changing my brake fluid but having never done it before I want to make sure I do it right. I've had a quick look in the manual and I know that you have to do it in sequence - passenger side rear, drivers side front, drivers side rear, passenger side front

You've got the sequence right anyway Shane. This is the way I did it:

1. From 2 drain points, (one front and rear), drain off as much of the old fluid without running the resevoir dry.
2. Fill the reservoir up with new fluid and repeat the same process, this time, from the other two drain points.
3. Fill the resevoir up again and bleed the brakes in the correct sequence.

Make sure you have 2 Lites of fluid just in case, there will be some wastage from the bleeding process. The important part is not to let the resevoir run dry so check if often during the process. When you've finished, pump the brake pedal to get the pressure back up again. If the pressure drops after a few seconds, theres still air in the system which means bleedin the system again.

Ciaran

Did you use a bleed kit? If you don't have a bleed kit do you just disconnect the brake pipe from the caliper? And do you not need someone to stand on the brake pedal to push the fluid out?