New Caliper or .......

[shrig1969]

Hello,
My steering has been pulling to the left for some time now, and a mechanic up the road pointed out that the caliper is pinching and may need replacing. Is it beyond a re-build? My intention is to replace the pads, flexi hoses and purchase a piston kit. Would like to hear from anyone who has tried this and succeeded or failed...
I have identified the caliper in question

Is this rubber not sitting correctly and causing the piston to stick?

Heres another view of the rubber seal with the caliper back on.

Does the pad look ok to you? The other was in a worse state.

Would Appreciate any advice......

[Ian Hulley]

It's frequently not financially viable to recon these things yourself .... back in the day it was 'normal' to re-seal a cleaned up piston and fit new dust seals but now ....

I was talking to the manager at Derby GSF the t'other week and they had an offer on exchange units of that caliper.

Ian

PS the pad looks fine.

[Aidan]

brakes always get a professionally rebuilt unit with a warranty on exchange
last pair I got from GSF one was new, probably chinese but works fine and had the correct bleed nipple, also came with the rubber boots and slider pins so they are a good deal imho

[California Dreamin]

Popped its dust seal so undoubtedly water has ingressed/corroded the piston to calliper bore.
Just get an exchange.
Pad wise: the one shown is very worn (95%) as it looks to be down to about 3mm (friction material) remaining. AND has a crack going through it....you need a new set.
New you are looking at around 12mm (friction material)
I would also at get 1.5 litres of DOT 4 and bleed all four brakes (including the clutch) whilst your at it.

Martin

[kevtherev]

Everyone wants to spend your money!
Seized caliper.
Remove the caliper from the hub.
Remove the pads
Pump out the piston
Remove the seal from the bore
Clean out the crap from seal groove
Clean up the seal
Inspect for rust.
Reassemble
Bleed.
Test.
Test failure? then do as the others suggest.

Repeat every 5 years.

[Bubble Meister]

I'd agree with Kev.
The piston can be cleaned with wire wool. Using oil, gently rub the wool to remove any light corrosion. If there's heavy corrosion you'll have to consider a new piston or complete caliper.

You could take the opportunity to clean the caliper (home made electolysis is good though ensure the piaton is still fitted and water doesn't enter the fluid ports).

[shrig1969]

Thanks for your varied responses. Yesterday I was looking at new Calipers, tonight I am searching piston seals. Big difference in price.
If my reliable mechanic will lend a hand, I will go for the seals. (Understand the seriousness of safety where brakes are concerned)
Will keep you updated after the parts have been ordered.

[kevtherev]

If it doesn't leak fluid from the caliper then the seals are just fine.
No need to fix what ain't broke.

Just remove the crap from behind the seal.
The build up of debris constricts the seal on the piston, eventually the piston cannot release the energy used to squeeze the disc.
The piston does not move under braking, it merely transfers the energy from your foot.

[shrig1969]

Kev,
The outer seal (dust seal?) is in a sorry state. The photo is not very clear but the rubber is split and twisted. The kits I have looked at are around a tenner so thought why not.
There has been no drop in brake fluid since I've had her.

[kevtherev]

Kev,
The outer seal (dust seal?) is in a sorry state. The photo is not very clear but the rubber is split and twisted. The kits I have looked at are around a tenner so thought why not.
There has been no drop in brake fluid since I've had her.

Hey it's your money, we're here to save you spending it!

Remember brake fluid should be changed once every two years.
Brake fluid is hygroscopic (absorbs water)
Water in you fluid is not welcome.
It causes one the issues you are experiencing now

[shrig1969]

Point noted.
Your knowledge is appreciated.

[shrig1969]

Ok, my parts have all been delivered.
Purchased a 11mm brake spanner and 5litres of Dot 4 today from Halfords.
Weather permitting I will start this job next weekend and update you all with photos when the work is complete.
Until then I will continue with the plus gas around the copper joints and bleed nipples......

[California Dreamin]

5 litres ... me and two of my mates will be around to have our brake fluid changed as well lol..
You'll need about 1.5 litres, 2 if you have issues, that includes bleeding the clutch.

Martin

[shrig1969]

5 litres ... me and two of my mates will be around to have our brake fluid changed as well lol..
You'll need about 1.5 litres, 2 if you have issues, that includes bleeding the clutch.

Martin

I know......but £10.99 for 1 litre or £19.99 for 5, what was I supposed to do? I'm a sucker for a bargain.

[kevtherev]

A sucker yes.