Hello all,

 

I know this question has been asked before but I can’t find any posts even using the search (could be me searching wrong)

This is for the 2009 MK2 FL VRS Octaiva!

 

On my last service the mechanic noted that the rubber gasket around the piston on both rear callipers was worn and letting dirt in. I’ve bought 2 rebuild kits for the rears however I was just looking for clarification on how the pistons come out. I know on the fronts I can use compressed air to blow them out as I have done that before, however with the rears I’m unsure if they need winding out or blowing out… or some total other method. Hope this makes sense.

 

Also with the rears am I correct in thinking I need a special tool to remove one bolt? M14 spline bit is what I vaguely recall needing?!

 

As always thanks for the help in advance.

 

Rusty

Edited 6 November, 20187 yr by RustyHill

I can only answer about the mk3 with electric handbrake. With that one, the pistons will come out just with compressed air. The M14 spline drive is needed to remove the calliper carrier (only need to remove if you want to replace the discs). Anyway, you can get a spine drive set from eBay for a tenner.

The caliper pistons on the MK2 octy (pre FL and FL, they use the same brake systems) need a windback tool, to remove or replace them. If the dust seals have worn and perished to the extent they are letting dirt in, then the best course of action to to replace the caliper as the dirt will have scored the bore and the seal kits will be useless and will soon leak fluid.

The new seals are an absolute pain to put in, the piston will need to be cleaned also but as mentioned above they will be scored or even pitted. Will get you by a few thousand but not a permanent solution. Buy new when can.

1 hour ago, Kris82 said:

The new seals are an absolute pain to put in, the piston will need to be cleaned also but as mentioned above they will be scored or even pitted. Will get you by a few thousand but not a permanent solution. Buy new when can.

At £200 a go I'll try my luck doing the repair, but I do get what you mean. When funds allow I'll get new ones for when these fail!

 

3 hours ago, Ju1ian1001 said:

The caliper pistons on the MK2 octy (pre FL and FL, they use the same brake systems) need a windback tool, to remove or replace them. If the dust seals have worn and perished to the extent they are letting dirt in, then the best course of action to to replace the caliper as the dirt will have scored the bore and the seal kits will be useless and will soon leak fluid.

Although the mechanic said it was letting dirt in I can't see any full splits in it, however that is only visual inspection and I am aware that it could be split and I'm not just seeing it. If there is damage when I take them apart I'll replace them.

 

6 hours ago, nicknorman said:

I can only answer about the mk3 with electric handbrake. With that one, the pistons will come out just with compressed air. The M14 spline drive is needed to remove the calliper carrier (only need to remove if you want to replace the discs). Anyway, you can get a spine drive set from eBay for a tenner.

Thank you, I thought it was a M14! I'll buy one tonight, they will have to come off to get at the seals properly! Having read what the others have said it would seem these ones wind out!

 

 

Thank you all for your replies it is much appreciated!  

M14 spline tool for the carrier bolts, 12mm or 14mm ring spanner or socket for the caliper bolts (can never remember which and i have done hundreds, must by getting old i think.) although there's no need to it is a good idea to take the carrier off and give the shoulders where the pads sit a good clean, also give the sliders a good clean and regrease, you can feel the huge difference it makes.

59 minutes ago, RustyHill said:

At £200 a go I'll try my luck doing the repair, but I do get what you mean. When funds allow I'll get new ones for when these fail!

 

Although the mechanic said it was letting dirt in I can't see any full splits in it, however that is only visual inspection and I am aware that it could be split and I'm not just seeing it. If there is damage when I take them apart I'll replace them.

 

Thank you, I thought it was a M14! I'll buy one tonight, they will have to come off to get at the seals properly! Having read what the others have said it would seem these ones wind out!

 

 

 

Thank you all for your replies it is much appreciated!  

 

Depending on the depth/amount of any corrosion you may be able to clean it up with some very fine sandpaper. Obviously this will only be a temporary repair but it will last a while - monitor for fluid loss.

 

Although as I said I have a mk3, I am puzzled by your need for an M14 spline drive. On mine, the callipers are removed by undoing two smallish bolts with an Allen (hex) key. This allows the callipers to be completely removed (well, you have to remove the hydraulic hose as well of course). The 14mm spline drive is only needed to remove the callipers carrier which you only need to remove in order to replace the discs. I would be surprised if yours had a 14mm spline drive bolt holding the callipers on, but I could be wrong (usually am!)

Wind the piston in, remove the arm for the handbrake from the rear of the caliper. With a rubber hammer or a piece of wood tap the bolt the handbrake mechanism into the caliper. This will push the piston out a bit, then using air blow the piston out. A foot pump will do if you don’t have a compressor. Use the plastic tapered connector that comes with pumps and apply it to the brake pipe inlet after you’ve removed all the brake fluid. Otherwise use some grips to remove the piston. I wouldn’t recommend reusing the  pistons as replacements are cheap enough. The piston will come out with the handbrake mechanism attached and it simply screwed off from there. 

With caliper now stripped remove the dust cover and the piston seal with a pick. At the back of the piston there is an o-ring remove this too. Clean up caliper and handbrake mechanism, ensure it’s free from dirt in the seal recesses and then put it somewhere clean like a carrier bag. Ensure the shaft of the handbrake is rust free too. Clean up the bench with fresh paper before reassembling. Apply red grease to the little o-ring and push it into place, same with the piston seal. Apply red grease to the handbrake shaft and the piston, screw the piston half way onto the screw. Feed the handbrake shaft through the piston seal and into the o-ring at the back of the caliper. Ease the piston through the seal twisting it onto the screw as you go. Once it’s through the seal pull the piston back and forth to ensure it’s smooth through the seal, it will be stiff until it beds in. 

With piston still protruding fit the dust seal, a little red grease helps push it in the recess. Once in secure with the metal ring, easiest to keep the open end of the ring away from the bridge of the caliper. This often the hardest part as you need to push the ring into the recess, which is allows a fight as you try not to puncture the dust seal. Once seated pull the dust cover out so the outer end fits into the recess on the piston.  Move the piston in and out to ensure the dust cover stays in place. 

Screw the piston back into the caliper until the hand brake spindle starts to rotate. Push gently on the piston whilst rotating and you will feel the lug on handbrake mechanism locate onto its recess. Refit the handbrake arm and use loctite on the nut. Rotate the piston so the pads indent line up. Change the bleed nipple if you’ve got one. If not remove with a socket to prevent rounding off. Clean it up and refit with a touch of grease. 

When you go to refit it the caliper, fill it with brake fluid before screwing it onto the brake hose as it makes bleeding much quicker. 

 

Edit.  This is all from memory but it should cover it all. Don’t forget to clean up the pad carrier and lightly grease the slider pins. 

Edited 6 November, 20187 yr by CWARD

I've found the calipers easiest to work on by:

1. Removing the 2 guide pin bolts using spanner and Allen key(?).

2. Remove the pads.

3. Orient the caliper up so that the lower guide pin can be inserted in the upper guide and the caliper is secured upside on its back with good access to the piston.

4. Pump the brake pedal slowly and check the piston protrusion repeatedly until it just comes loose.

5. Using locking grips pinch the rubber brake pipe approximately 3cm from the caliper fitting, just pinch enough to stop fluid flow, do not crush.

6. Remove the piston and both the outer dust seal and inner fluid seal.

7. Clean in hot soapy water and assess repairability, the pistons are PTFE coated so may not be rusted, check/clean caliper bore/seal groove.

8. On reassembly ensure cleanliness/dryness.

9. Slacken bleed nipple.

10. With mating/sliding parts lightly lubricated with fresh brake fluid, insert the fluid seal in the caliper, slide the dust seal over the piston, offer the piston/seal to the caliper and work the piston around like stirring a bowl to help the dust seal pop into place.

11. Once seal and piston are fitted and ready to be rewound fully into the caliper, either use a proper tool or improvise with wide pipe grips to grip the very end of the piston and rotate bit by bit to screw it in.

12. Tighten the bleed nipple, remove the self locking grips and refit the caliper and pads as they came off.

13. Bleed and test before driving.

 

Not an exhaustive how-to but good enough for anyone with a mechanical aptitude.

 

You do not need any special tools.

Edited 6 November, 20187 yr by MicMac
Alzheimers!

1 hour ago, nicknorman said:

Depending on the depth/amount of any corrosion you may be able to clean it up with some very fine sandpaper. Obviously this will only be a temporary repair but it will last a while - monitor for fluid loss.

 

Although as I said I have a mk3, I am puzzled by your need for an M14 spline drive. On mine, the callipers are removed by undoing two smallish bolts with an Allen (hex) key. This allows the callipers to be completely removed (well, you have to remove the hydraulic hose as well of course). The 14mm spline drive is only needed to remove the callipers carrier which you only need to remove in order to replace the discs. I would be surprised if yours had a 14mm spline drive bolt holding the callipers on, but I could be wrong (usually am!)

 

 I think I am getting myself mixed up, you are correct there is no need to remove it, I was remembering when I had to change something else which required it's full removal!

 

 

 

 

Thank you to everyone else also, this has given me far more confidence to do the work and what tools are needed!

Thank you! :-)

 

3 minutes ago, RustyHill said:

 

 

 I think I am getting myself mixed up, you are correct there is no need to remove it, I was remembering when I had to change something else which required it's full removal!

 

 

 

 

Thank you to everyone else also, this has given me far more confidence to do the work and what tools are needed!

 

Thank you! :-)

 

 

 

Thats correct just remove the caliper,the carrier can be left bolted to the vehicle; only needs to come to change the discs, you can clean up the carrier with it still bolted to the vehicle.

I know this is an old thread, but the post by CWARD is of interest to me.  I'm currently restoring an old caliper off my Octy PD 1.9Tdi Estate and I cannot figure out how to remove the handbrake spindle.  Everything else is off but I need to get the spindle out as it's damaged from being seized.  Is it possible to get this spindle out, or is it new caliper time?

 

Thanks in advance for any replies!

1. Remove piston from calliper.

2. Undo nut on handbrake lever and remove lever.

3. Tap shaft inwards through calliper.

4. Remove shaft seal on calliper.

5. Upon reassembly I recommend fitting a new o-ring on the shaft, the outer seal can be cleaned and packed with silicone grease.

Thanks mate.  I've tried tapping the shaft through the caliper but it won't budge.  I was a bit hesitant as I didn't want to damage anything and didn't know which way it was supposed to go anyway.  I've even given it some heat.  Do I need to give it a harder bash or even press it out?  Also, I take it there's a spring somewhere on the shaft?

 

I'll need a full kit including the seal behind the actuator arm - any tips where I can find them?

 

Cheers

 

 

Have you removed the piston?

Yes, piston is out - stuck fast!

If you've cleaned the shaft as much as possible and applied some penetrant fluid you'll just have to knock the shaft until it goes through-take care not to mar the threads.

 

The steel shaft sits in a brass bush which is fitted to the alloy calliper, I wouldn't imagine the bush is available as a spare part.

 

Clean shaft/bush thoroughly and dry fit to check for smooth free operation.

 

Don't worry overly about it, the inner o-ring is to seal brake fluid in and the outer seal is to prevent dirt ingress to the rotating shaft, if you reassemble with silicone grease on the shaft/bush/seal you'll be good for years unless you go off roading, if you want new outer seals you'll just have to search online or ask a VAG dealer.

 

 

Spot on mate, thanks very much.  I always put the nut on before giving it a bash with a nylon headed hammer.  I could just push it out, which would probably be less risky.  I take it the inner o-ring is the one that sits in the recess near the top of the piston in the bore and the outer seal is the one that sits behind the handbrake arm.  It'll be the latter that'll be more difficult to find, I reckon, although I think I could modify an existing seal to do the job.

No, there is an o-ring seal on the inner side of the handbrake actuator shaft, knock the shaft out and you'll see.

 

As I said don't worry about the dust seal, it's to prevent dirt ingress to the shaft/bush and isn't a pressure seal, refit well greased.

Cheers pal, I'll have another go at it tomorrow!

 

@beezera10

 

*** IMPORTANT ***

 

Apologies, I forgot to mention that there is an internal circlip holding the handbrake mechanism in the calliper, remove it and it should come apart easily... Alzheimer's!

 

1. Remove piston from calliper.

2. Undo nut on handbrake lever and remove lever.

3. Remove internal circlip from calliper which secures the handbrake mechanism.

4. Tap shaft inwards through calliper.

5. Remove shaft seal on calliper.

6. Upon reassembly I recommend fitting a new o-ring on the shaft, the outer seal can be cleaned and packed with silicone grease.

Edited 9 April, 20215 yr by MicMac

Just seen FatblokeVRS's video!  Thanks pal!