My car's just failed the MoT

[suffolkpete]

Handbrake not working at all on the right hand side   The problem seems to be that a little wedge-shaped piece of metal  that sits between the cam and the adjuster was missing, so that the cam just went straight round to the stop without doing anything useful.  I've spent the day replacing it, using a part from a spare caliper and all seems to be well now.  What really annoys me though, is that the car had only done a few hundred km since the last test when I bought it so what cowboy passed it last time?  There was no way it was ever going to work in that state and I don't think it can have simply fallen out, besides there seemed to have been an attempt to bodge it by fitting extra shims under the adjuster.  Rant over!  On the positive side, it was given a very thorough inspection by the tester, who had never seen one before and everything else seemed ok.

[roy4matra]

Handbrake not working at all on the right hand side   The problem seems to be that a little wedge-shaped piece of metal  that sits between the cam and the adjuster was missing...

It was actually missing Peter?  Not just stuck in the grease inside the rubber boot?

What really annoys me though, is that the car had only done a few hundred km since the last test when I bought it so what cowboy passed it last time?

Yes, if the boot was still on and the wedge was not in there, then it could not have worked!

However, please read my brake booklet, where it explains that the handbrake lever has only limited travel.  If it is pulled any further then it will knock the wedge out.  So the handbrake could be working one moment and suddenly fail on the next application.  This is common when the caliper and/or handbrake is not adjusted correctly so it's important to get it right.

Roy

[suffolkpete]

No, the wedge was not inside the boot.  The footbrake worked well and the self adjusters seemed to be working.  I can't see how it would be possible to apply enough force to knock the wedge out if everything's set up correctly.  The discs look almost new, in fact the tester commented on their good condition.  Just have to put it down to experience.

[roy4matra]

... I can't see how it would be possible to apply enough force to knock the wedge out if everything's set up correctly.

I can assure you it does not take much force as the push is on the side of the wedge and as you pull the handbrake up it flips the wedge out.  See me at a meeting and I'll show you.  The point is the handbrake must be disconnected preferably and the lever fully back, to set the self adjustment via pedal pressure.  Then reconnect the handbrake, but do not adjust it so that it pulls the lever forward in the off position.  The lever must be fully off for the adjuster to work.

Roy

[Oskar]

o crap 
i did the overhaul and didnt do that last step for the selfadjustment

is it possible do redo those steps afterwards or has hell broken loose? 

[roy4matra]

o crap 
i did the overhaul and didnt do that last step for the selfadjustment

is it possible do redo those steps afterwards or has hell broken loose? 

No, it's no problem.  Simply back off the handbrake and disconnect it at the caliper levers.  Then make sure the levers are fully off and against their stops.  Now either pump the pedal hard with the engine running or drive it up and down the road and use the brakes to set the self adjuster inside the rear caliper.

After it is set, you should notice (with the car jacked up and the wheels off the ground, that only a small movement of each lever forward should start applying the brake on that wheel.  (the pad should be virtually touching the disc but with no pressure on it)  The lever should return to its stop without any help.  Do the same both sides.  Now reconnect the handbrake cable and adjust so that the slack is taken up but it does not pull the levers off their stops, otherwise self adjustment cannot take place.

The handbrake should now be able to hold easily without excessive force or movement.  Job done.

One point: If the pads are new and the discs old, and the pads are not yet bedded in, the handbrake will not be very effective until they are bedded in and might need re-adjustment at that time.

Roy

[valross]

Do I use the same method adjusting the Bagheera handbrake?

Lasse

[roy4matra]

Do I use the same method adjusting the Bagheera handbrake?

Lasse

Yes, exactly, as they use the same calipers.

Roy

[valross]

Thank you!

[suffolkpete]

Passed now!  Handbrake efficiency 23% when set up as per Roy's recommendations.  Tester reckoned we were a bit light on the weight though, we used 1000kg.  Anyway, a year's Murena driving to look forward to, if nothing breaks.

[macaroni]

Passed now! 

 

Well done, great news.

Anyway, a year's Murena driving to look forward to, if nothing breaks.

Haha, I admire your optimism...!

[roy4matra]

Passed now!  Handbrake efficiency 23% when set up as per Roy's recommendations.  Tester reckoned we were a bit light on the weight though, we used 1000 kg...

Actually that is exactly the correct specified weight for a 1.6 Murena as it happens.  The 2.2 is 1050 kg.  However, strictly, when the car is not on the brake weight chart and not listed on the M.o.T. computer, testers are supposed to do an inertia meter road brake test, so he was wrong to guess a weight in the first place.

I went through this with the authorities, at the beginning of the computerisation of the M.o.T. as we had another car that 'failed' on hand brake performance but hey had used too heavy a weight.  I offered to supply all the specification weights for all Matra cars, but they insisted that as they were not listed, the only way a tester is allowed to do the test is with the inertia meter and a road brake test - no roller test.

So if anyone has any problems and they have used a roller test you can point out that it is incorrect.

Roy

[suffolkpete]

He didn't guess the weight, he asked me and I suggested the weight in line with your recommendations, which he accepted, I think it was the good performance of the brakes when properly set up that introduced doubts.  Perhaps the garage that did the test last year used an inertia test.  The performance on one wheel was 12%, so it may have scraped through on a good day.  Still, he never charged me for the re-test, so I'm happy at the end of the day, having found and fixed a fault I didn't previously know about.