172 Cup Rear Brakes - New parts and still playing up!

[Chris_Beer]

So...


Replaced my rear discs and pads a couple years ago... as the OSR caliper had seized and destroyed the old ones. Free'd up the caliper with copper grease (not ideal) and an hour of brute force. Everything seemed good again.


Last month, the car had been sat around for a while after a track day, I noticed this...

I decided the corroded / sticky caliper wasn't worth messing around with again, and maybe the track day killed it once and for all.


I ordered / fitted (thanks @George@RTR_Parts):

A pair of re-conditioned Bosch Calipers from GSF
New Renault Discs / Bearings
New Renault Disc Spacers - Flat Side to Disc, Tapered towards the car
New Rear Hub Nuts - Torqued to 175nm
New Brembo Pads - Nipples on pads in the piston slot
New Fitting Kit
New Renault Handbrake Cables
ATE Typ200 Fluid (Super Gold)
New NSR Renault Brake Pipe - Flexi to Caliper (The union twisted and s**t itself)
New Gunson Eezibleed Kit
All other bolts torqued to correct setting

Brakes bled - I did my traditional non ABS furthest away first - NSR, OSR, NSF, OSF

The OSR caliper - This was the only caliper that did not release any fluid easily unless the pedal was pumped

Pumped the pedal on all calipers doing a final / second bleed until I had used all the new fluid (but not below the minimum line on the bottle), and held the pedal down whilst locking off the nipple.



TEST DRIVE - 6 to 8 Miles - Normal Driving:

Front Discs - Both Warm / Hot to touch after a few seconds (It's 2c here tonight)
Rear NS Disc - Warm but nothing more
Rear OS Disc - Too hot to touch and noticeable heat!


I don't want to ruin all these new bits, PLEASE can CS help me out with this! ersevere:

Thank you

 

[NorthloopCup]

That could be the compensator valve mate. @George@RTR_Parts can supply these as well I believe.

 

[Tarmac Adam]

Agree could be a faulty compensator it's underneath the car at the back the brake pipes go in to it check the arm / piston if free but for the cost I'd be tempted just put a new one on especially as you've already spent so much they at quite prone to seizing and causing back brake issues other than that could be a master cylinder issue but I'd be looking at the compensator first

 

[Chris_Beer]

Would that cause slower fluid bleeding.. more so on one side?

I suppose if fluid isn't reaching the caliper properly maybe its making it stick on or something?

This is where we get into Cup compensators lol... Just done a search and there are hundreds of opinions that they are either preset from factory, or still adjust even without being connected to the rear beam

Thanks so far !

 

[jamesycc]

rear compensator as its the only thing not replaced I guess. About £80 from ecp for a Bosch one using their 30% discount code.

 

[Pauleds]

Faulty compensator sounds like it passes fluid with the pedal then it is not letting it return to the m/c properly meaning a build up of back pressure on the caliper. The bit of pressure it has is leaving that caliper on and is heating up the disc.

 

[Chris_Beer]

Thank you @Pauleds .... That makes sense about the slight pressure! ersevere:

Just had a look...

What I'm not unsure about, is the bar upto the boot floor... Is this someone making up for spring that keeps it up tight (missing on mine) ?

Doesn't look great! Makes me a little bit sick seeing it lol

 

[bloke]

you'll be needing to sort brake pipes as well when you sort that out, couple of them look like they'll snap the pipes when you undo the union.

 

[npt]

Remove the home made bolt holding the swing arm, lubricate it and work up and down, it's likely seized, I was having the same issues so just renewed the whole lot, pipes,flexi's, compensator, callipers etc all round, should be trouble free for a few years

 

[Chris_Beer]

you'll be needing to sort brake pipes as well when you sort that out, couple of them look like they'll snap the pipes when you undo the union.

Hmmm indeed, the rear caliper one was the same, but as said was able to renew that section alone.

What do you think, hope for the best and if they go then replace the lines needed?

@George@RTR_Parts - Are they available?

Remove the home made bolt holding the swing arm, lubricate it and work up and down, it's likely seized, I was having the same issues so just renewed the whole lot, pipes,flexi's, compensator, callipers etc all round, should be trouble free for a few years

My worry is how long will it last in that condition. Also without the bolt thing holding it, won't it just be flapping around a little so to speak?



Thank you everyone for the help so far !

 

[George@RTR_Parts]

yes I can get you a new compensator valve and lines mate @Chris_Beer

 

[Chris_Beer]

PM'd @George@RTR_Parts - Thanks again bud

I'm itching to get under the car and check the unions but its hailing so bad car alarms are going off

 

[Freeman13]

That little spring will hold it in place. As said above lubricate and work up and down.

 

[Chris_Beer]

It's stopped hailing (now it's dark... !)

Cleaned up and lubed. Tried my brake pipe spanner on the two bottom pipes, left spun the hole pipe instantly, the right wanted to round, FKin tight.

Can't get to the top ones, but they will be the same story.... @bloke you were right, the caliper one was so easy!

Removed the DIY bolt, and swing arm now moves after whacking it, but only if yanked up and down.

I think it maybe very hard to save it, and even so, it will last about 5 minutes ?

The only thing keeping me going after this, was that I cleaned it earlier after 3 months

But with this temperature, it just makes me see it as a fridge freezer...

So...

New Compensator and Lines time... ? 😧

 

[jamesycc]

had to do mine for the mot. Wasn't sending a drop of fluid to the o/s rear caliper, had 3 brakes for a while.. Didn't notice it until it was replaced and made quite a difference. They get so corroded cos,of where they are.

 

[Chris_Beer]

yeah I remember you saying about your MOT bill @jamesycc!

Think these cars our at the age now where the weather takes its toll. To be fair its 13 years old, and travelled 135,000 plus miles...

Did you have to replace your pipes as well or were you lucky

 

[jamesycc]

yeah I remember you saying about your MOT bill @jamesycc!

Think these cars our at the age now where the weather takes its toll. To be fair its 13 years old, and travelled 135,000 plus miles...

Did you have to replace your pipes as well or were you lucky

just the o/s pipe and hose in the end. The rest were fine.....for now!! Yeah they're getting on a bit now these cars. Mines a daily so goes out in all weather which doesn't help. Tbh I paid my garage to do the work as I didn't have the time with 4 kids, could have saved a few hundred quid but I didn't fancy getting under a car for hours on end and getting asked if I've finished yet..

 

[Chris_Beer]

Don't blame you, it's wearing thin with the clocks now changed and it being less than 5c or dark the past couple of weeks. Mine's been off the road for nearly 4-5 months in total this year!

Now i'm questioning using it in the winter 😂

 

[tomsteer]

I was on my back under my cup that's been off the road sine 2012 yesterday... I got the compensator moving pretty freely after a few wiggles and plenty of fluid bleeding through so hopefully it will just be the usual "the brakes are meant to be like that, look at this VOSA document!" conversation come MOT testing. I too had the wife asking how much longer i'd be... aka stop fannying about with that and come and look after your daughter so i can cook the dinner!

Have you tried bleeding since you've freed the valve up? I've never seen a bolt holding it up like you had, just loads of cables ties normally.

Looks great in white, hope you sort the issues out soon!

 

[Chris_Beer]

I was on my back under my cup that's been off the road sine 2012 yesterday... I got the compensator moving pretty freely after a few wiggles and plenty of fluid bleeding through so hopefully it will just be the usual "the brakes are meant to be like that, look at this VOSA document!" conversation come MOT testing. I too had the wife asking how much longer i'd be... aka stop fannying about with that and come and look after your daughter so i can cook the dinner!

Have you tried bleeding since you've freed the valve up? I've never seen a bolt holding it up like you had, just loads of cables ties normally.

Looks great in white, hope you sort the issues out soon!

The arm moves but stays wherever you leave it. Very tough and doesn't look great, so doubt it will last.

The bolt has probably been there for years, I certainly haven't touched it in 3 years, so maybe a garage did it for an MOT...

Thanks Tom - Once this is done I might update my thread... it's been a while, and more has changed than meets the eye... but mostly maintenance ersevere:🙈

 

[Killer Sound]

Hi Chris, my valve was pretty bad and I thought they might snap when they remove the brake lines, but managed to free them up and out. I found on another thread about the valve in question that might help. Even if the arm goes up and down does not mean it is working, it has an internal valve, that opens and closes via a spring and if it's knackered it wont allow pressure to the brakes. I copied and pasted it below. I am sure if you can replace it, you should have no bother for quite a few years. Good luck, I hope you get it sorted.

As i saw it when i replaced and bled my rear brakes the valve should be open at rest ( might be the wrong way round ) , when you press the brake pedal the valve will then start to close thus limiting the amount of pressure applyed to the rear brakes. On releasing the brake this valve should then re-open and reset the system.
The small spring that already exists applys the force to pull the valve open (Resting position), now over time this gets weak and no longer opens the valve. So when you come to reapply the brake the valve is closed and wont allow any pressure to the rear brakes resulting in NO (and i mean no) braking.

To test this theory i jacked the back of the car up - pushed the valve to the point where it is closest to the body (open i think) and span the rear wheels , i then put the brake on and the wheels stopped. I then took my foot off the brake, span the wheels and braked again (without touching the valve), this time the wheels carried on turning. so i then manually pushed the valve (Open) again - reapplyed the brakes and the wheels stopped leading me to belive that the spring was no longer returing the valve to its working position.

 

[Chris_Beer]

Hi Chris, my valve was pretty bad and I thought they might snap when they remove the brake lines, but managed to free them up and out. I found on another thread about the valve in question that might help. Even if the arm goes up and down does not mean it is working, it has an internal valve, that opens and closes via a spring and if it's knackered it wont allow pressure to the brakes. I copied and pasted it below. I am sure if you can replace it, you should have no bother for quite a few years. Good luck, I hope you get it sorted.

As i saw it when i replaced and bled my rear brakes the valve should be open at rest ( might be the wrong way round ) , when you press the brake pedal the valve will then start to close thus limiting the amount of pressure applyed to the rear brakes. On releasing the brake this valve should then re-open and reset the system.
The small spring that already exists applys the force to pull the valve open (Resting position), now over time this gets weak and no longer opens the valve. So when you come to reapply the brake the valve is closed and wont allow any pressure to the rear brakes resulting in NO (and i mean no) braking.

To test this theory i jacked the back of the car up - pushed the valve to the point where it is closest to the body (open i think) and span the rear wheels , i then put the brake on and the wheels stopped. I then took my foot off the brake, span the wheels and braked again (without touching the valve), this time the wheels carried on turning. so i then manually pushed the valve (Open) again - reapplyed the brakes and the wheels stopped leading me to belive that the spring was no longer returing the valve to its working position.

Wow thanks for the comprehensive post @Killer Sound !

I'm pretty much sold on the valve not operating as it should. @George@RTR_Parts has me sorted, and I hope this sort the fluid bleeding being slower on the hot disc side! Thankfully I don't need to use the car so hasn't been driven on anymore than the short test drive.

Nearer the weekend things should be a little clearer RE: brake lines, but so far, things aren't looking good!

 

[Tony Hunter]

Wow, what a mess under there!

 

[MrBlonde]

View attachment 168628

Sorry not on topic but,Great looking clio mate!:up:.have you a build thread or anymore photos?

@Chris_Beer

 

[George@RTR_Parts]

Wow, what a mess under there!

They'll be a shiney new compensator valve and new lines under there soon mate :up:

 

[Chris_Beer]

Wow, what a mess under there!

Amen, the joy of the untouched parts of a road car. The worst mechanical part of the car by a mile! All needs binning!

View attachment 168628

Sorry not on topic but,Great looking clio mate!:up:.have you a build thread or anymore photos?

@Chris_Beer

Hundreds pal, link to the thread is in my profile but it goes back a fair while... time flies and its very out of date now from the work in past few months.

just takes so damn to update, pull and find the photos and upload it all!

They'll be a shiney new compensator valve and new lines under there soon mate :up:

All this from a hairline cracked disc lol... good thing it did crack tbh... I think...

The front started with a leaky CV boot... but lets not go there

 

[Chris_Beer]

I have the compensator off the car, the magic of a blowtorch! :up: @npt you weren't wrong.

This was with some multi-gas mostly butane, had my doubts not using mapp gas.

View attachment 171028

I've now contacted @George@RTR_Parts again as the small brake lines, brackets, bolts, and mostly everything in the photo is a pile of scrap lol.

Of course some new braided lines too, I went for solid blue ones as they match the Bilsteins

 

[shiftspark]

Photo not working ^
Looks like mine will need similar work.

 

[Chris_Beer]

Photo is ok here? I uploaded it on here? Try a refresh of the page.

Strangely after heating everything, the compensator clicked and now moves freely, which in turn has got the spring working very well and feeling smooth and springy. But the inside bit itself is still sticky and whole thing looks like scrap.

Just want to crack on now as it's been a month !!

 

[shiftspark]

@Chris_Beer Hi mate I am having problems with both sides binding on mine. I have wound the pistons back in and the sliders seem free enough but still bind. I also adjusted the hand brake as it was non existent, do you have any other tips before I end up renewing everything . I have just booked it in for a cambelt so it's looking like an expensive month ahead:tired: also would you mind messaging me the price of all the bits you changed?
Ta

 

[Chris_Beer]

@Chris_Beer Hi mate I am having problems with both sides binding on mine. I have wound the pistons back in and the sliders seem free enough but still bind. I also adjusted the hand brake as it was non existent, do you have any other tips before I end up renewing everything . I have just booked it in for a cambelt so it's looking like an expensive month ahead:tired: also would you mind messaging me the price of all the bits you changed?
Ta

Hello mate

Have you perhaps adjusted the handbrake too tight? Have you checked the condition of the compensator? Are both sides getting hot?

 

[shiftspark]

Yep both sides hot. I was thinking about it before I think the handbrake has got worse since I've had it even after fitting new discs,pads etc as it was also missing the spacer washer behind the disc. I am wondering now if the handbrake mechs are sticking as I had to adjust the rod under the heat shield along way?.

 

[Chris_Beer]

Seems strange for both sides to do it?

Perhaps your right on the handbrake mechs but I have no idea how you reset them?! If the pistons move freely and the carriers slide and new discs and pads etc then has to be that or the compensator.

 

[shiftspark]

Update.
Checked the compensator and it was cable tied up, cut it off and freed up the lever which works with the spring and feels ok. I removed the off side pads and found the piston was quite difficult to turn back in but after a lot of freeing off got to move ok checked the arm for the handbrake and was ok. Tried the brakes a few times and it was a lot freer than before.
Onto the other side and the piston moved easily but the sliders were stiff when pulled out wards so spent some time freeing it off then tried the handbrake lever which didn't feel right so whipped the cover off and it looks like the wedge that presses the piston inwards to operate the handbrake has slipped so I stripped it down but could not get it back in so gave up :tired: looks like I will have to take them off and send them to Bigred for a rebuild ffs !!

 

[Chris_Beer]

Hopefully after freeing stuff up a little it begins to behave again mate but for me I didn't want to destroy another set of discs and pads etc hence replacing the whole lot.

The handbrake side of the rear calipers are mean't to be a complete pain and almost impossible some have said.

If I were you, get yourself a GSF 48/49% discount code this weekend or usually on Wednesday and get some refurb units, then return your old ones for the surcharge. Check out my thread for pictures. Do not use ECP as they initially sent me two different makes, one with a pad carrier, one without, then said the carrier was a mistake and asked for it back. GSF ones came as complete Bosch refurbs and with the discount code and surcharge back they aren't badly priced at all.