Rear nearside brake "thumps" at times.

[daverclasper]

Hi. I have had this issue for a couple of years.

It's ok for a while (but only about 200 miles), if I adjust the shoes up on that side, which is usually a couple of clicks (offside rarely needs tweaking up) .

I thought it may be due to those recesses that the handbrake pivot can make in the brake plate, causing a sudden jump in cylinder movement, though have welded those up and smoothed the surface.

Rear brakes both working ok for MOT, though nearside, was grabbing more.

Always a lot more shoe dust in the nearside drum/area, as though working harder?

Have changed cylinders, in case sticking, still the same and bled,bled and bled.

Also the cylinders seem to move smoothly across the brake plate, with the shoes/springs removed.

So wondering.

Adjuster slipping somehow?.

Drum wear out of spec (though have swapped them over and still same issue on nearside) ?.

Worth trying new cylinder clips (black best. Iv'e heard), in case there's bit more tension, than a rattling good fit.  

Any clues great please and have a H.N.Y

Cheers, Dave 

 

Edited December 29, 2019 by daverclasper

[Pete Lewis]

have a look at 

drum retaining screw  head makes contact with the wheel    ( distorts the drum when wheel is fitted)

make sure rear shoe is right way up ( ie spare hb slot at bottom )

check tie rod bushes etc.

Pete

 

 

[Nigel Clark]

2 hours ago, Pete Lewis said:

have a look at 

drum retaining screw  head makes contact with the wheel    ( distorts the drum when wheel is fitted)

make sure rear shoe is right way up ( ie spare hb slot at bottom )

check tie rod bushes etc.

Pete

 

 

Check all of the above, as Pete wisely suggested. One other thought... Could the slave cylinder be loose in its slot in the backplate?

Check that the retaining clips are present and correctly fitted, replace with new if in doubt. Also ensure the slot in the backplate where the slave cylinder fits  hasn't worn to cause excess free movement.

Nigel

PS: worn rear trunnion bushes or play in wire wheel splines could also cause such a mystery 'thump', though neither would explain the excess brake dust.

[Colin Lindsay]

Check the rear hose, too. If the hose has collapsed or is restricting fluid flow then all else will move before that one, hence the thump when it finally frees up; similarly it will be slower to release after braking hence the extra wear. Have a look at the pipe to that wheel too in case there's a kink or dent.

[Pete Lewis]

and dis connect the handbrake cable   then lock up the shoe adjustment hard,   reconnect the cable to a nice fit , no tension,    and back of the sdjusters to free the wheel dont do this with it 'hanging ' best jacked to running height .

Pete

[daverclasper]

Cheers chaps and HNY to you.

Got some things to try now.

Is there a way of accurately checking the hose hasn't collapsed internally please?.

Thanks, Dave 

[Nick Jones]

4 hours ago, daverclasper said:

Is there a way of accurately checking the hose hasn't collapsed internally please?.

Not really..... without taking it off, at which point you may as well fit new.

You should also check that your slave cylinders pistons are free moving (moving grudgingly is not good enough). The shoes I have fitted on the Vitesse now initially appeared to be producing epic amounts of dust (had to remove the drums and knock them out twice a year to prevent judder) and wearing fast for no obvious reason. However, having found a partially seized slave cylinder in pre-mot checks this spring and renewed both the problem has gone away.....,

Nick

[daverclasper]

17 hours ago, Nick Jones said:

wearing fast for no obvious reason.

Thanks Nick. Were the shoes not releasing properly?.  I assume it's not the cylinders on mine, as replaced to try and solve problem a whole back, though I know assumptions, not always correct.   

Dave

Edited January 3, 2020 by daverclasper

[Nick Jones]

Well, I thought they were releasing and the brakes weren’t dragging excessively, but the dust was incredible with build-up in the drums enough to cause judder within 1000 miles and adjustment needed more often than that.  I did blame crappy shoes initially (for about 2 years in fact), but as I said above I had to fit new slave cylinders back in May and have done nearly 4K miles since (including lots of Alps) without needing to adjust or knock the dust out - and the shoes are the same ones.....

Nick

[daverclasper]

Nick, How did you determine they were sticking on the pre MoT check, please?.

Dave