Xantia Front Brakes Overhaul

Post by **admiral51** » 24 Aug 2009, 18:56

Hi All

I need to strip down the front brakes/calipers on my VSX as im 99% sure they are binding on.
Under normal cicumstances i would be replacing both disks and pads along with the handbrake cables as i need to eliminate as much as possible but it looks like im only going to have the cash replace the HB cables

I am aware the front caliper pistons need rewinding but are they as easy to strip apart as the rears.Can i remove the pads and have the pistons operating the same as on the rears to clean them/cover them with LHM

I am going to have to refit the existing pads unfortunately but as the caliper swings up and away from the disk would it be sensible to remove the caliper from the car completely to do this "overhaul".I think the only brake pipe on the fronts is the flexi hose which i replaced less than 3 weeks ago so not too concerned about having to undo it again

All comments gratefully recieved

Colin

citronut · Post by **citronut** » 24 Aug 2009, 20:23

simple answer no the front callipers have basicly two pistons one inside the other, and in the rear behind the lever is a set of conical spring washers,

there is a special tool to compress these washers on refitting, i belive there is also a worm drive type of ratchet,

quite often if the front callipers are binding and the cables are good, it could be either sticking pads which had been fitted dry (no copper slip), or the calliper slide at the top pivot has got hard dry grease or water ingres,

the other thing it the lever is bindding at its pivot in the rear of the calliper, just lube and work it till it swings back fully off on its own

regards malcolm

Stempy · Post by **Stempy** » 24 Aug 2009, 22:01

I recently overhauled my front calipers as I was changing the discs and pads also ( as you may remember). They weren't actually binding though, I just did it while I was in there. I think if there is any stiffness its likely to be in the sliding pins rather than the piston.

I cleaned out all the old hard grease and replaced it with some brake grease which I got from ebay. All the rubber boots were in good nick so didn't need replacing. I think it would be much easier to remove the caliper to do a really good job of it.

Post by **CitroJim** » 25 Aug 2009, 08:38

One thing to check Colin is that the piston gaiters have not split, let moisture in and rusted the pistons near the ends.

If the old pads were very, very worn and the pistons were paractically right out and the gaiter split, rust can form on the exposed part of the piston. When the piston is retracted to install new pads, this rust may prevent the piston moving freely and thus cause a bit of binding. It will not necessarily be given away by LHM leaks.

More than likely though, as siad, it's either the slides need a good clean and grease or the pads arebinging in te caliper frame. I always find the caliper frames (where the pads slide) need a really good clean-up before the pads will slide freely.

VertVega · Post by **VertVega** » 25 Aug 2009, 22:47

After reading above replies there is not much to add.
To prevent binding I clean metal parts with a small copper/iron brush (also brake cleaner spray). Then I apply some copper paste, brake grease and grease to the locations as marked in the picture.

I usually take care of the below issues to prevent binding:
- caliper sideways movement (pivot lubrication nr 1)
- all gaiters not damaged or cracked
- brake pads sliding easily
- hand brake cable not damaged (check around first circular guidance)
- spring mechanism not rusted. lift up the rubber protector(number 2), clean and fill it with grease. cable tier to fix

Post by **admiral51** » 29 Aug 2009, 20:48

Thanks for the replies guys looks like i will be attempting this overhaul this weekend

Just one small problem how exactly does the caliper undo from the main arm on its swivel point

Cheers

Colin

VertVega · Post by **VertVega** » 30 Aug 2009, 08:29

Brake caliper grease can be applied without caliper undo. Turn caliper upwards. Slide it to end limit and gently lift rubber seals of slide from ends with a small flat head screwdriver. Add some caliper grease and slide caliper from end to end couple of times. I do this treatment once a year, especially before winter season. It saves a lot of trouble. (

Release handbrake cable and pull it off the hole on the caliper. Take care that you don't release the other end of the cable under the car.
Then you will have "how to fit HB cable" job

This picture is taken before the cleaning and greasing process, with all the dirt, rust and brake dust

I never had to remove piston during overhaul. Just clean it while it is still out and rewind because it is already having a LHM bath

Here is before and after picture 8)

VertVega · Post by **VertVega** » 30 Aug 2009, 10:22

admiral51 or someone else, when you replace flexi brake hose, do you depressurize system? What's the most usual cause to replace it, I mean do they start leaking, having cracks or some other reason? I still have the originals and it is for sure they don't last forever

VertVega · Post by **VertVega** » 30 Aug 2009, 12:48

also if someone knows flexi brake hose size, diam etc. can you pls write shortly.

Stempy · Post by **Stempy** » 30 Aug 2009, 23:14

Just make sure you don't let them get to this stage........

http://forums.vwvortex.com/zerothread?id=4534625

Post by **myglaren** » 30 Aug 2009, 23:33

Hmmmm. That disk does look a little on the thin side.

VertVega · Post by **VertVega** » 30 Aug 2009, 23:50

Thanks for your reply Mike, it seems to be much easier than I thought. I will check during day time their condition.

Stempy, those US cars with powerful engines (V6...V12) deserve proper Air-cooled brake discs

Fortunately we are only dealing with French cars here

Post by **admiral51** » 02 Sep 2009, 21:48

Hi VertVega
Sorry for the long response intermittent connections to the web(OK i forgot to pay the bill

)

I seem to remember that someone said the brake union fitting sizes were dependant on whether or not ABS was fitted but cant seem to find it just now

Thanks for the pics very helpful but have yet to start this job as other things reared their ugly head over the weekend,fingers crossed for this weekend

As superloopy says i didnt release the pressure when i did my front hoses

Colin

Post by **admiral51** » 02 Sep 2009, 21:52

One last question

Do both calipers rewind in the same direction cos if anyone can make a hash of this job its going to be me

Colin

VertVega · Post by **VertVega** » 02 Sep 2009, 22:05

It's good to hear that they helped a bit

As a rule of thumb, (for Xantia

) regard each front brake caliper piston as a screw and rewind clockwise to tighten.