172 Cup Rear Brake Efficiency - MOT Failure

[CamMoreRon]

Evening all..

I know there are quite a few topics on this, but my 172 Cup has just failed on rear brake efficiency (RBT Service Brake Efficiency: 45%). I gather from all the old threads that there was a VOSA note to testers explaining that the Cups have poor rear braking, or something along those lines, but I can't seem to find it and none of the links in the old threads work. Does this still apply, and if so, does anyone have the note handy so I can take it to my MOT station?

The car has CL5 pads front & rear, so I explained to him that they might just be cold and need a warm-up, but he told me that he didn't expect it to make much difference. I might try putting the std. pads back in for the sake of it, but I'll only switch them back immediately so I'd rather not waste the effort.

 

[Steven103]

Attached.

View attachment 104929


EDIT: Sorry, didn't really read your post properly. That's the VOSA newsletter that I believe you've read about, but that refers to when you fail an MOT because the tester thinks there is a physical part of the braking system (the rear bias adjuster) missing from the car (Renault kept some ABS related bits on the Cup just for manufacturing convenience). Failing due to a lack of rear brake effort isn't what the above note is about.

 

[Dr HMS Derv Destroyer]

Vosa info for these still apply, I can't find the docs tho

 

[Deek1182]

MOT d-day tomorrow for me. Had huge issues with this last year and turned out it was a goosed load sensing valve. Here's hoping things go a bit better this time round and no need for arguments!

 

[peanuthead]

This happened to me, you can take the document and argue. But best thing is to cable tie the compensator value up. Read through the linked thread work for me

http://www.cliosport.net/forum/showthread.php?707197-Cup-MOT-failed

 

[CamMoreRon]

Thanks for the replies chaps. The guy said that you could turn the wheels with little effort, so it's probably likely that the compensator valve is fudged. I swapped the pads on August and checked that the pistons and sliders were free, so it can only really be that. How much is the compensator from Renault, out of interest?

 

[Deek1182]

New valve is expensive (around 200 quid).

I found mine was blocked and wasn't sending fluid to o/s/r caliper. I removed the brake lines then used brake cleaner and compressed air to free off which solved problem. After all that f%&ing about tho the thing packed in the next day. I managed to PIC up a 2nd hand one which seemed to do the job.

Think the biggest prob with the cups is not having the spring (although I doesn't need it) meaning the lever doesn't get moved and ultimately seize over time.

 

[CamMoreRon]

For anyone who's interested, Euro Car Parts have got the valve for £91.20 so I'm going to give that a go.

 

[peanuthead]

Have you tried to cable tie your value like the thread I linked?? As cup rear brakes do very very little normally

Deek- the lever should move as the brakes pressed, the spring is actually to hold the spring up when braking increases. As the lower the lever the less rear braking. Therefore cable ties hold it in the up position meaning max breaking. Although beware it will lock up easier on the rear

 

[CamMoreRon]

FFS.. I took it down for a re-test this morning and the guy has still failed it! I handed him the document about rear brake performance on these cars and he said he'd have to call VOSA on Monday to make sure it's legit. :banghead:

 

[Matt W]

Had the exact same issue with my cup. The guy thought i'd photoshopped the vosa document. What a flannel.

 

[peanuthead]

They didn't want to listen to me when I showed them it either. Have you tried the cable ties yet?

 

[CamMoreRon]

Not yet, no. I'm going to go to another place and cable-tie it beforehand to avoid all this rubbish.

 

[peanuthead]

Honestly takes 10 minutes and will solve your problem.

 

[MattPc]

Cam,

Did the original MOT station call you back after speaking to VOSA for clarification of the waiver doc?

 

[CamMoreRon]

No they never got back to me! I just phoned them and he said he hadn't spoken to VOSA, and that the document I showed them was just a "Matters of Testing" document, rather than an actual VOSA bulletin, so he won't listen to it. He tried telling me that the rear brakes had zero force, but that's a load of rubbish as it registered 30kg or so on the rollers and you could clearly see the rear suspension compress when he applied the brakes. I've booked it in at another garage for this afternoon and wil tie the compensator up, so hopefully that sorts it.

Edit: This is the same guy who tried to tell me a cable handbrake has better mechanical advantage than a hydraulic footbrake because "it works off a lever".

 

[CamMoreRon]

Passed. :clap:

 

[peanuthead]

Did you cable tie the lever??