Rear brake efficiency

[dauphin]

My Felicia (a 1998 1.3LXi) will be due for an MOT within the next month. Last year I had a fair bit of trouble getting the rear brakes to meet the requirements of the test, so I thought I would see if anyone here has had a similar problem or has any solutions to suggest.

Initially the car failed on service brake efficiency (33%), which the tester said was down to the rear brakes - although the handbrake passed. I took advantage of Kwik-Fit's free brake inspection offer but, somewhat to my surprise, they found nothing wrong and all they could suggest was fitting new brake shoes. I declined that offer, but then stripped the rear brakes myself. There was plenty of meat left on the shoes, but to be on the safe side I fitted a new set of shoes. There was no sign of any fluid leakage and as far as I could tell the wheel cylinders worked normally and the drums looked in good condition.

When I took the car for retest, they said the brakes were better, but still just failed to meet the test standard. I explained to the tester that neither Kwik-Fit or I had been able to find anything wrong, and he offered to try adjusting them. After doing so, he said that the brakes had again improved slightly and had fortunately gone from a marginal fail to a marginal pass.

I asked the tester if he had any ideas why the rear brakes did not appear to be as powerful as they ought to be and he said it is a fairly common problem with light cars like the Felicia; there is not enough weight on the back wheels for the tyres to grip the brake rollers and I could try sticking a bag of cement in the boot before the next test!

That doesn't sound to me like an ideal solution. I also found when I drove the car away from the test that he had adjusted the rear brakes up so tight that there was no free travel in the handbrake and I am fairly sure that if I had presented the car in that condition it would have failed on that ground!

So what do I do this year? Have others had this problem? I would have thought that the brakes ought to breeze through the test if they are operating as they should.

I wonder whether, if the problem is really down to inadequate grip on the rollers, it could have been the fault of the tyres - one of the rear tyres earned an advisory last year and I replaced them both immediately after the test.

The only other thing that occurred to me was that the tester entered the car on the garage records as a Favorit. I pointed this out to him and asked if the computer could be calculating the wrong brake efficiency as a result, but he said no, if anything it would work in my favour that the car was tested as a Favorit.

Any suggestions would be welcome.

[cheezemonkhai]

I'd make sure your spare is in if it's legal and do as the man says and go via a garden centre for an 80L bag of compost of some sand myself.

If you had them checked and they were all ok, it won't hurt to take the persons advice. If nothing else it will rule out the grip issue if it still fails.

[anewman]

The rear brakes are the same as a late (93 on) Favorit appart from the Felicia has ABS, and I believe are based on or are the same as a VW Polo Mk2.

I do not know if this post helps you http://briskoda.net/technical-guides/felicia-fav-fel-fab-oct-drum-brakes/49988/

I assume the foot pedal isn't feeling spongy?

What brand are the brake shoes? The OE one's are ferodo I believe.

I assume the drums have been checked for ovality?

[fordfan]

There is a load limiting valve attached to the rear beam axle on the drivers side if I remember correctly. These quite often seize or become sticky, try lubricating it up and working it in.

[daverapid]

It's quite common for rear wheel cylinders to sieze on Felicias.

[dauphin]

Thanks for all the suggestions.

I may have to try the weight in the boot idea, although I can't help feeling it should not be necessary, otherwise everyone here would be saying "me too"!

The foot pedal feels fine and the brakes give me no concerns in normal driving. Can't now say what brand the shoes were as it was a year ago but unless they were some outrageous counterfeit rubbish I can't believe they would struggle to meet test standards - and anyway the problem was already there with the old shoes.

I wondered about the load limiting valve;didn't know it could be stripped/serviced, so may well have a look at that.

I don't think the wheel cylinders could be seized completely as there would be no braking at all on the affected wheel, but perhaps it is possible that they have got a bit sticky so that's another possibility.

[KenONeill]

I can't help thinking "line limitter" too, particularly if you rarely to never run the car with anyone in the back, or anything in the boot.

[dauphin]

I really thought this was going to be the answer, but I've been under the car this morning and cannot see any load-sensitive valve at the rear. I think my car must have the alternative "pressure-sensitive" valves described in the Haynes manual, which are attached to the master cylinder, in which case they either work or (unlikely I'd have thought) they don't!

I am assuming that these are the valves you can see in the attached picture?

[johnh510]

Our '98 Lxi Estate has had some attention to a load limiting valve "under the back" by a semi-tame MOT tester in the past to get it through.