Front caliper release condition

David Lawrence · 30th December 2016, 12:49

In November my 2001 cdt conn se passed its MOT but the tester mentioned my drivers side caliper was not releasing as well as the passenger one. It was still acceptable in his opinion but warranted checking out, which i did the same day.

I concluded that the pads were slightly corroded in to a groove in their carriers, so scraped off the rust, and went on my way until more time for a better job.

Today i released the carrier, removed the pads, filed away all the corrosion in the carriers, polished the guide pins and lubricated them, tested the caliper piston retracted and extended freely, applied copperslip to the pad hooks, the carrier contact points and put all back together.

Result is exactly the same as before i started, the driver side still doesnt release quite so freely as the passenger side. But i now know that everything is as it should be as far as external parts of the caliper and pads are concerned.

Is there anything internal to the caliper that might cause this phenomenon?

The pads show no signs of overheating, and the car runs freely downhill once brakes are released, and there is no pulling to left of right. Beginning to think about maybe obtaining some refurbished calipers.

JoeMc · 30th December 2016, 13:24

If there's cack in the piston, it'll be as you say... Could be that the pins are still not as released as they should be as well

A good excuse to uprate the system to the ZT 190 brake calipers, discs and pads

If that's a no-go, then yes, refurbished calipers will be the next thing to sort

beinet1 · 30th December 2016, 18:54

Pull the piston and seals out of the caliper. Give both a good cleanup and refit together with new seals. Check that the piston slides easily inside the caliper bore before putting the new seals in.

COLVERT · 30th December 2016, 18:58

--You've done everything else,---

HarryM1BYT · 30th December 2016, 21:08

Disk brakes don't spring back when released, the pressure from the piston simply disappears when the pedal is released.

Mike Noc · 31st December 2016, 07:34

Quote:

Originally Posted by beinet1

Pull the piston and seals out of the caliper. Give both a good cleanup and refit together with new seals. Check that the piston slides easily inside the caliper bore before putting the new seals in.

Had to do this on a couple of occasions. Luckily everything cleaned up without needing to replace anything other than the seals on the 75, but our Freelander needed a new piston as well due to corrosion.

David Lawrence · 31st December 2016, 08:36

Quote:

Originally Posted by Mike Noc

Had to do this on a couple of occasions. Luckily everything cleaned up without needing to replace anything other than the seals on the 75, but our Freelander needed a new piston as well due to corrosion.

Did yours behave the same as mine? I mean the piston appears to slide in and out quite freely so I am not sure why it wouldnt do so when the pedal pressure is released.

David Lawrence · 31st December 2016, 08:41

Quote:

Originally Posted by beinet1

Pull the piston and seals out of the caliper. Give both a good cleanup and refit together with new seals. Check that the piston slides easily inside the caliper bore before putting the new seals in.

Will try and find a source of new seals then. Might turn out cheaper to get a refurbished unit, think i saw a supplier recommended a few days ago somewhere.

Fusilier · 31st December 2016, 08:57

Quote:

Originally Posted by David Lawrence

Will try and find a source of new seals then. Might turn out cheaper to get a refurbished unit, think i saw a supplier recommended a few days ago somewhere.

David

Two Options, one is to replace Caliper, as Ronnie did the other day

http://www.the75andztclub.co.uk/foru...d.php?t=259101

or buy a complete refurbishment kit from Big Red Brakes

http://www.ebay.co.uk/itm/Rover-75-F...kAAOSwwE5WXdXi

Stu

Mike Noc · 31st December 2016, 09:16

Quote:

Originally Posted by David Lawrence

Did yours behave the same as mine? I mean the piston appears to slide in and out quite freely so I am not sure why it wouldnt do so when the pedal pressure is released.

To be honest David both were sticking quite badly. It doesn't take much resistance to cause a problem though.

On one of them I didn't have any new seals so just cleaned everything up, lubricated the old seals with fresh brake fluid and refitted the piston.

30th December 2016, 12:49	#1
David Lawrence This is my second home Rover 75 CDT-2001 Join Date: Jan 2009 Location: Wrexham, North Wales Posts: 3,606 Thanks: 195 Thanked 606 Times in 501 Posts	Front caliper release condition In November my 2001 cdt conn se passed its MOT but the tester mentioned my drivers side caliper was not releasing as well as the passenger one. It was still acceptable in his opinion but warranted checking out, which i did the same day. I concluded that the pads were slightly corroded in to a groove in their carriers, so scraped off the rust, and went on my way until more time for a better job. Today i released the carrier, removed the pads, filed away all the corrosion in the carriers, polished the guide pins and lubricated them, tested the caliper piston retracted and extended freely, applied copperslip to the pad hooks, the carrier contact points and put all back together. Result is exactly the same as before i started, the driver side still doesnt release quite so freely as the passenger side. But i now know that everything is as it should be as far as external parts of the caliper and pads are concerned. Is there anything internal to the caliper that might cause this phenomenon? The pads show no signs of overheating, and the car runs freely downhill once brakes are released, and there is no pulling to left of right. Beginning to think about maybe obtaining some refurbished calipers.

30th December 2016, 21:08	#5
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	Disk brakes don't spring back when released, the pressure from the piston simply disappears when the pedal is released. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

30th December 2016, 13:24	#2
JoeMc Loves to post MG ZT V6 / BMW E60 M5 Join Date: Sep 2016 Location: Bamber Bridge Posts: 372 Thanks: 34 Thanked 62 Times in 51 Posts	If there's cack in the piston, it'll be as you say... Could be that the pins are still not as released as they should be as well A good excuse to uprate the system to the ZT 190 brake calipers, discs and pads If that's a no-go, then yes, refurbished calipers will be the next thing to sort

30th December 2016, 18:54	#3
beinet1 Posted a thing or two Rover 75 2.0 V6 Auto Join Date: May 2011 Location: Sandnes - Norway Posts: 1,560 Thanks: 64 Thanked 283 Times in 174 Posts	Pull the piston and seals out of the caliper. Give both a good cleanup and refit together with new seals. Check that the piston slides easily inside the caliper bore before putting the new seals in.

30th December 2016, 18:58	#4
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	--You've done everything else,---