18 replies to this topic

[ChrisS1]

I've got an issue where the hand brake mechanism on one of the rear calipers will not return the pads so it basically sticks on. I need to whip the wheel off to check whether the external return spring is present and correct.

 

From reading up on old posts I understand that once the hand brake mechanism fails the only option is to replace the caliper?

 

I know FLD is messing about with rear calipers recently so wondered whether there was any update on how the mechanism actually works (is there an internal and external spring) and whether it can be repaired, as other than that the caliper works fine.

[Nev]

There is an external captured spring that can't really go wrong. Check the rust/friction factor on the cable + sheath itself - this is the likely culprit at a guess.

Edited by Nev, 29 March 2017 - 09:54 AM.

[ChrisS1]

Unfortunately not. I disconnected the cable and it moves freely in the sleeve.

 

I forgot to check the external spring so hoping its that.

[Nev]

Unfortunately not. I disconnected the cable and it moves freely in the sleeve.

 

I forgot to check the external spring so hoping its that.

 

Ooh, sounds like the piston is a bit siezed or your spring has somehow failed. Most likely the former. You can wind the slave piston in and out a few times and it will likely free up.

 

[ChrisS1]

Tried that - with the cable detached there is no binding at all. Wound the piston in and out a few times. As soon as you apply the handbrake the wheel locks. When you release the handbrake the cable goes slack but the mechanism stays on.

 

I can't recall whether the external spring was present or not...

 

On reading up it sounded like there was some sort of internal spring as well that sometimes fails?

[CHILL Gone DUTCH]

is the wire inside the hand brake cable lose 

[ChrisS1]

Eh? You mean the cable within the outer sleeve? If so yes, it runs freely within the outer.

[Johnboyhgt]

its a complex mechanism for the job it does and basically consists of ball bearings and ramps which effectively wedge the brakes on, has your caliper been in bits before ?

Edited by Johnboyhgt, 29 March 2017 - 10:58 AM.

[ChrisS1]

Not in my ownership, might have been previously.

[Nev]

Sounds to me like you need to get it on the bench for a good poke around. Maybe pre-buy a replacement to keep you on the road?

[Johnboyhgt]

Good guide here as to what the gubbin's looks like.

 

http://wiki.seloc.or..._Brembo_Caliper

[ChrisS1]

[Johnboyhgt]

If its the piston seized they can be bought from Big Red Calipers - google will reveal the site address. they are listed for a Renault 21 turbo from memory.

 

Its a pig of a job to strip down and rebuild and fraught with problems along the way.

[ChrisS1]

Just skim read through that guide and it certainly looks like an involved process!

 

Lets hope it's just the external spring missing....

[Johnboyhgt]

Its not so bad if its just a piston or seals etc - if its more involved then it will be a pita !

 

Happy to guide you through - or do it for beer tokens if needs be.

[FLD]

I have some spare guts if needs be. Just give me a shout.

[Mat Jackson]

Chris - I had mine sticking and struggled to get it resolved. I took it to Andy at Qmech and he refurbished both for me Sent from my iPhone using Tapatalk

[Andyeddie]

Nelly VX is selling used rear Calipers on here. That's the route I would take. Sounds like overhauling rear Calipers is fraught with pitfalls.

[ChrisS1]

FLD has bought them all.