Rear Brake Caliper

[coastline taxis]

when trying to remove a rear brake caliper the 2 securing bolts are absolute pigs to get out. Now if you look at the front of the caliper (where you slot the pads in) youl see a circle in each corner scrape all the crap out of it then squirt brake cleaner in then wd40 using the straw that comes with it to get right in. These holes go straight onto the bolts that hold the caliper on. Now undo the 2 torx screw that hold the disc on and by the time youve done that the wd 40 has performed its magic and the result is the caliper comes of no problem at all. Takes us 30 mins a side now

[Johndouglas]

Since 1989, having had a BX and two Xantias I know what a b****** of a job it can be getting calliper bolts out. With my present C5, at the end of the first year, I removed one bolt at a time, gave it a smear of grease and replaced it. I do it now as part of the maintenance programme.

[techbod]

so were are talking about the caliper carrier bolts which only need removing when changing the discs, yes they can be a pig but think of other ways to work them like as taxi says and grease should not be used on the bolts because they vibrate loose, to unbolt them use heat ant tap bolt heat with a hammer to break the rust up then applying wd40 this should free them up

[Johndouglas]

grease should not be used on the bolts because they vibrate loose,

 

Maybe that's the theory - In practice, if they are torqued to 35lbs, in a year's time when I want to redo them, they are as tight as when they were put in....................................and they come out without too much effort.

[techbod]

well in fact they should have locking paste on the threads by the book ;)

[Johndouglas]

well in fact they should have locking paste on the threads by the book ;)

 

Yes - I've heard it said that they put Loctite on them when they are assembled in the factory, but the ease with which mine came out at the end of the first year makes me doubt it. To my mind it's the later corrosion from the unlike metals that binds them. Most guys on the various forums recommend greasing the bolts before refitting. Certainly according to Haynes, they say, "Lubricate the threads of the calliper securing bolts, then refit the calliper and tighten to the specified torque." That's good enough for me!

[techbod]

caliper holder not caliper carrier, the carrier is fixed and caliper is free to move, caliper carrier is a separate UNIT FROM THE CALIPER

 

edit # my appols I hit the caps lock button accidental like ;)

[Johndouglas]

caliper holder not caliper carrier, the carrier is fixed and caliper is free to move, caliper carrier is a separate UNIT FROM THE CALIPER

 

Quite

[coastline taxis]

Quite

No its not just when removing the disc a very comming fault on the c5 is when the back brake caliper push out over onto the road wheel and start scraping it or you start having trouble getting the rear pad in.This is caused by whitchcraft happening where the alloy caliper mates up to metal. And if left unchecked it will cost you a new caliper. And to be honest weve never put threadlock on them yet

[kfk]

Some excellent comments here guys, to what has started off as a usefull tip.

 

The important issues here are the fact its a job that is a pig to do when you have to do it and that the bolts have locktite along the whole length of the bolt......knowing that you are going to have to do it at some point in the vehicles life and at regular intervals thereafter its worth building it into your maintenance schedule, before you need to replace the pads, they will last longer that way.

 

upon reassembly it is important that locktite is used on the bolt threads, and from experience i would also recommend the use of a torque wrench when tightening as the threads in the rear suspension arms are prone to stripping if overtightened......i would also recommend replacing the bolts and washers as they also have a tendency to snap.

 

The manufacturer does recommend loctite along the whole length of the bolt.....but then they dont have to get them out later do they?.....so as to whether you do it is personal preference, and if your maintaining your own vehicle i'm sure you will be checking them when you inspect your brakes.

 

And dont forget, if you leave the 8mm bolt tightened you dont end up with brake fluid all over the place when you remove the caliper.....you dont really want to bleed them ...do you?

 

Allow plenty of time, have the right tools available and the job will go well.

[paul.h]

'squirt brake cleaner in then wd40'

 

When I did mine, WD40 on its own did not help as much as I would have liked so the brake cleaner must be the magic ingredient to reduce the effort with the 500mm breaker bar undoing and removing the bolts. I have experience of stripping the threads in one hole on the suspension arm and then the bolt snapping and have posted this previously on the forum. You can almost imagine in the car factory the technicians laughing as they inject 150mm of loctite on each bolt as the brakes are assembled.

 

Something to note is the bolts are a higher tensile strength than normal high tensile ones - they are 10.9 (usual HT ones are 8.8) and are not widely available. Normal size is 10mm x 150mm. If you strip the suspension arm threads you can put in a longer bolt that goes through the hole and put a HT nut on the back so it needs to be at least 160mm - try and get one of these in 10.9 - I could only get an Allen bolt which is even higher tensile (12.9 I think). Note this may not be an official fix but it worked.