Cup MOT failed

[peanuthead]

I know this has been covered before so I know that the rear brake performance is low. However the mot station said they were not doing anything, i.e push the brakes and the wheels keep spinning. So I'm guessing this is wrong

Any suggestions?

 

[Saner]

Search the forum for the VOSA declaration that states what the actual spec should be? Then, with that in hand, discuss with the MOT station if any further work is required?

 

[sam JFM]

Unfortunately they can still fail you.

 

[peanuthead]

I have the article but it doesn't mention exactly how poor they can be? Should the rear brakes stop the car on the rollers they use?

 

[mark123]

They should show some effort.

Try cable tieing the compensator valve up (search) and see how they perform.

 

[The Chubby Pirate]

Page 8;

[FONT=.HelveticaNeueUI]http://www.dft.gov.uk/vosa/repository/MoT%20Issue%2031%20-%20Apr%202006.pdf[/FONT]

 

[peanuthead]

Right just jacked the car up and putting the brakes on has no affect on the rears. Can spin them easily by hand. Surely this isn't right?

​Any ideas what it might be?

 

[mark123]

Mine you can just turn by hand but not easily. Have you tried cable tieing the compensator up? If that doesn't affect things it is probably knackered. Could be lots of things though.
​

 

[Andyrg@ ClioTurbo]

The breaks should still have some resistance. And if they dont there not working.

My cup had the same issues. I replaced the break bias valve and them one wheel would stop turning the other didn't. Ended up fitting a new caliper as well.

 

[rsRob]

Check the calipers aren't seized?

 

[rsRob]

Free them off with mole grips (careful not to damage the piston) and lube them up

 

[peanuthead]

Mark, looking at the picture you put up in the other thread think I may not have. There was a lever on the compensator valve that pulled down, take it this was the wrong bit??

I will have to take of the rears and have a look at the pistons.

 

[Andyrg@ ClioTurbo]

Cups do NOT have the spring bar from the compensation biad valve to rear beam.. this is why they fail more commonly than the full fat

 

[mark123]

I don't really understand, put a picture up.
​

 

[peanuthead]

Fred removed the spring bar when it went in for a service as the previous owner had fitted one.

I meant the black lever part in the picture is in an up position normally and you can pull it down. Which bit should I be tieing up?

 

[Fred@BTM]

does the arm move freely? it if does and the brakes still don't work then i'd suggest new rear pads and bleeding the system, they should work a bit (not very well)

 

[peanuthead]

Yeah it moves freely, I remember you saying it looked brand new when you serviced the car in December. The rear pads seem to have a lot of material left on them, or wouldnt that matter?

I will take the rears off later to check they arent seized and give the system a bleed.

 

[Kerwall]

The rear pads will have loads of meat. The rear brakes arnt working

 

[mark123]

In normal operation when you press the pedal the black lever moves down to reduce effort to the rears. If you get someone to press the pedal while you put your hand on the lever you will feel it move.

If you fix it in the up position with cable ties you should get more rear effort.

 

[Cup_Phil]

They should show some effort.

Try cable tieing the compensator valve up (search) and see how they perform.

This... I've got a cable tie from the arm up to the chassis holding it in the up position. It's passed MOT's for 3 years like that.

Also whip your rear pads out and make sure the caliper sliders are still actually sliding - if they're not get them moving again. They rust up very easily

Last time I had issues with them seizing up I just bought a pair of calipers off ebay for £30 with half the mileage mine had on. The same calipers are used on 306's,106's,most renaults... loads of cars. Very common so very cheap to replace

 

[sam JFM]

Make sure the arm returns to its "closed" position - if it does not return then you wont get any effort.

jack it up so the rear is off the ground,make sure the valve is closed and pushed all the toward the body and get someone to press the brake - you should have rear brakes

Now release the brake and re apply - its possible that they now wont work, if that is the case I would recon its a good bet that the small spring on the arm has gone weak and needs assistance.

I added a spring to mine so it would return fully (I have it in a thread somewhere on here).

Just to add; I know the cup had no bar attaching it to the rear beam, I was not trying to simulate that. The spring I added was to help the original (tiny) spring so its job

 

[Cup_Phil]

^^ Yeah or just cable tie the thing up lol

 

[sam JFM]

Yeah lol but at least with the spring you do get a reduction in rear effort

 

[Cup_Phil]

Considering you could jack a cup up - put your foot fully on the brake and still turn the rear wheel by hand, I'd rather not have lol

 

[peanuthead]

Had a better look today with someone to help. Brakes did just about hold with the lever moving down. Now I have tied it up seems much better, will take the print out along aswell and hope for the best. Thanks everyone for all the help

 

[Cup_Phil]

Good luck

 

[peanuthead]

It passed fine! Is it best to keep the ties on now or take them off now?

 

[mark123]

Good news. I don't as I once locked up the rears with them on. Lots of people do keep them on without problems though.
​

 

[Edges]

This... I've got a cable tie from the arm up to the chassis holding it in the up position. It's passed MOT's for 3 years like that.

Also whip your rear pads out and make sure the caliper sliders are still actually sliding - if they're not get them moving again. They rust up very easily

Last time I had issues with them seizing up I just bought a pair of calipers off ebay for £30 with half the mileage mine had on. The same calipers are used on 306's,106's,most renaults... loads of cars. Very common so very cheap to replace

Are the entire rear brakes the same as those other models you mentioned? Or just the hydraulic part?