Help please on rear brakes....

hopefully I can attach pics here for calipers and handbrake cable ! looking at everything I cannot see how it fails to offer enough braking to fail MOT but it does! I am beginning to suspect a pad/disc issue as surface is like looking in a mirror .very highly polished compared to my modern car with dull metal discs. so thinking of changing pads to another type and roughing up surface of disc with enemy cloth! see if. friction increases? handbrake cable slack is about 20mm with actuating lever arms on calipers back on stops ( about 2-3mm away actually) when cable is tuat after pulling handbrake on ..I have actuating arms about 50-60% along travel path? not sure I explained that bit well but do check pics. 9BF8D29E-A636-44A7-939F-5629AC40E14D.jpeg34E9EF50-BB05-430B-859F-B03D57DF02F8.jpeg
 

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I've only just managed to see the pics in full, and it all looks to be where it should be apart from the springs and shims on the slippers being the wrong way around, but the amount of travel on the quadrants between "OFF" and "ON" looks more than I would like to see so I think they could benefit by being ratcheted up more at the initial setting.

You could also try deglazing the pads and the discs.

The quadrants should be back on their stops at rest, and as soon as the lever is pulled up there should be no appreciable slack in the cable, once the lever starts moving, so should the quadrants.

With the handbrake off, if you push the caliper and outer pad up against the disc, how much movement can you feel on the inner pad?
 
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PS. When you get the MOT brake readings, are they low for both the foot and hand brake, or just for the handbrake only?
 
Agree ith Harvey. With the handbrake off see how much you can rock the caliper side to side. if there is a lot of movement you can easily remove the outer pad by undoing the bolts and then ratchet the quadrant click by click until the outer pad is a sliding fit. That should give you a good brake.
As suggested by H it looks like the quadrants are moving a long way when the handbrake is applied.
 
been under cr today for 4 and bit hours . removed discs . check calipers swing across easily ( both do ) so no friction on pivot pin issues. pads. are good but roughed surface with 80 grit paper. then removed high mirror. finish on discs with emery cloth creating a 'cross hatch' dull pattern. all refitted. and test on driveway after pumping footbrake and operating Fahd brake many times was ... in D with engine idling can just about hold car..if revved handbrake July applied .. car. will move forward overpowering brake ( hand) at around 1200 revs. so I think I have a pad issue and possible excess slack in tensioning cable? got to try and see if theres a better 'pad' put there with more friction .I hear green stuff ? is good but cant seem to find any for a rover p6 V8 :(
 
You have to manually set the clearance and not rely on handbrake and footbrake. You need less clearance than those two methods provide.
See Harvey's post #22
The engine will over power the brake, so not a fair test.
 
You have to adjust the pad clearance to .010 in. (0,25mm) with the adjustable bolt then operate the handbrake several times and then recheck the pad clearance.
 
will be a while b4 I can get under the old lady to check things as busy times next few weeks . as to engine overpowering brakes at 1200 revs.. I can attest on my old zpephy mk4 when applying hand brake if you let clutch on and added throttle you would more likely stall or get large burins smell! was happy to leave such a large heavy car on a handbrake on any hill. This rover sadly simply seem's to have very poor adhesion/friction even when I am pretending to be the hulk and going green pulling hand brake up with both hands ( 4 clicks) suspect calipers are Ok ( both replaced courtesy of Wins) as were all brake pipes plus Flexi.servo .master cylinder .rear discs and all pads. goes through Mot on. foot brake so looks like a silly mechanical issue I am missing. handbrake cable is good ( look brand new. with easy movement and no friction when. operating by fingers when disconnected from rear brake mechanism. operating each lever on. callipers by hand when turning rear wheel by hand gets instant grip and stops ( cant compare my weak arm muscles with an engine or weight of a car on a hill) so will have a look at pad adjustment yet again. though wife new getting slightly insistent I get rid of car! with luck and weather permitting Intend to visit Enfield museum 'icebreaker' which I think is in February but have to check dates as away first 3 weeks of that month. idea to hopefully chat to other V8 series 2 owners and have them test my handbrake for comparison. see if they can keep car on handbrake at 1200 revs ( if they are kind enough) anyway soon be another year and spring coming plus dreaded Mot failure time.
 
Nightmare Green, I have read everyone posts from the start this must be a very frustrating situation for you but dont give up.
As cobra said the handbrake should hold the car with with no problem, and he should know legend has it Cobra only goes round corners sideways with full lock on the handbrake ;)
Green you should not need to sand the brakes even if they are new they should work
personally I would set up the rear brakes to the best I could I would then look into other areas of whats going on and start from the beginning and look forward of the car to see whats going on look at the most simplest of things first because it sounds like everything that might not have worked you have replaced or checked its working so if you set up the rears brakes to the best of your knowledge look further on and see what other parts are doing when you apply the handbrake.
 
I don't know about the sideways bit, but the current handbrake I have is the best I have ever had on any classic car, so I have no complaints.

I should add that this is due to this forum and its contributors providing advice and guidance.
 
sadly can't get to whitewebbs all rover event February now as away. not giving up just yet but having been through just about all I can think off ..gives a long list .. new serve and master brake cylinder. new pads all round both rear calipers replaced. with new discs. new handbrake cable .flexi and solid brake pipes replaced. check as far as possible adjustment on cable and movement on calipers but wondering if 'self adjustment' isn't working on calipers . so another day under car in new year is likely :( still think pads are 'polishing' discs and that will reduce friction. sanding off polished surface made no difference so looking at pad material ... was suggested. green /redstuff are better but not fond a supplier yet ! it is suggested they are sutabekl for road and track use and are up to 20% more friction . that. may well eb difference to a yearly fail on handbrake and a pass :)
 
I would advise not spending your money on uprated rear pads to cure a handbrake problem. Uprated pads will not improve a handbrake, as it is the clamping force, or lack of it that is the problem.
You will likely not find any uprated pads for the rear anyway, I got my Mintex ones custom made. They made a marked improvement to the rear brake performance, so much so that the front brakes need uprating further now, so by just fitting better rear pads you will have unbalanced brakes.

I think if you make sure that the piston cups ratchet out with every click of the quadrant by removing the pads and observing closely, then set up each caliper to have a close running clearance between disc and pads, with the quadrants on their stops with the brake off you will cure it.
 
Yes exactly. The reason why Harvey advises disc in/out when setting clearance is because you can’t get a strong enough bite with the calipers with the disc in as it retracts too far when released.
Think of the disc as a gauge block. You want to just be able to slide it in the retracted distance. That way the contracted bite will be where it needs to be for very good brakes.
When you fully understand how they work you realise it’s impossible to get them that good without taking the discs out.
Jim
 
The reason why Harvey advises disc in/out when setting clearance is because you can’t get a strong enough bite with the calipers with the disc in as it retracts too far when released.
Think of the disc as a gauge block. You want to just be able to slide it in the retracted distance. That way the contracted bite will be where it needs to be for very good brakes.
When you fully understand how they work you realise it’s impossible to get them that good without taking the discs out.

I've lost count of the times I've tried to explain that, and the above is more concise than I've ever managed. Short and to the point. Normally my fingertips end up bleeding....
 
I have just been looking at my spare set of rear calipers and a set of new pads. I have noticed that the holes in the new outer pads for the pins to locate in are not very deep, they have pad lining material in them and when you offer them up to the caliper and screw in the pin the pad gets jacked off the face of the caliper.
It could be the CG's pads are being held off the caliper by a too shallow hole in the pad, this could be the reason he cannot get the vital last couple of clicks on the adjuster. It could be that the material in the hole is a bit spongy and will be compressed by the power of the footbrake, but will be stopping hand brake adjustment. There is no reason these holes cannot be deepened with a drill / Dremel to make sure there is adequate depth to allow the pad to seat on the caliper.

I also notice that it should be possible to get adjustment by removing the outer pad and clicking the quardrant and then testing clearance by sliding the outer pad in and out rather than having to remove the disc. The outer pad should act as a gauge block in the same way as a disc does.
 
I have just been looking at my spare set of rear calipers and a set of new pads. I have noticed that the holes in the new outer pads for the pins to locate in are not very deep, they have pad lining material in them and when you offer them up to the caliper and screw in the pin the pad gets jacked off the face of the caliper.

If you set them up properly sliding the disc in and out that will be compensated for, and if you set up by sliding the outer pad in and out while ratcheting, then on completion when the pin goes in it will make the running clearance tighter not looser, too tight if you have ratcheted them up to the correct point.
 
Yes I can understand that. What I cannot get to grips with is the pad resting on two points of contact ( bolts ) and not the full width of the caliper.
It cannot be right that the whole pad rests on such a small point area. Surely all the bolts do is stop the pad being spat out by the disc rotating.
 
Yes I can understand that. What I cannot get to grips with is the pad resting on two points of contact ( bolts ) and not the full width of the caliper.
It cannot be right that the whole pad rests on such a small point area. Surely all the bolts do is stop the pad being spat out by the disc rotating.

I'd agree,, which is the reason that back in the day I only fitted genuine Girling pads and never had any problems of that nature. Now in the days of "repro" this and "NOS" who-knows-what it's a different ballgame altogether.
 
In between my last post I thought exactly that. I bet the importance of having those holes 'dressed' after the bonding on of the pad has been lost.
It makes sense that the hole has to be deep enough not to hold the pad off the caliper. In theory if the hole was very shallow the force could blow the pad off the back plate.
 
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