Rebuilt rear brakes not working.

WarrenL

WarrenL

Active Member
Righto gents, here's this morning's puzzler.

My rear brakes are all back in the car (minus the anti-rattle spring that KiwiRover is sending me, but that can go in later). But they don't work!

Handbrake or the wife holding down the pedal, I can still spin my rear wheels. I went for a quick drive around the (quiet) block to operate everything a few times but to no effect. Back on the stands, and neither the handbrake or the pedal are producing the goods. What's gone wrong?

I'll have another go at bleeding them this morning, due to the wife's inability to properly understand commands like "in" and "out", but there seems to be plenty of pedal pressure. Did I wind the pistons in too far in order to get the new pads in? There is only regulation gnat's hair clearance between the discs and the pads. Did John the mechanic mess up the caliper rebuild (unlikely - he's a thoroughly competent chap).

Another mystery. I seem to strike them quite often - almost as often as I touch something on my P6.
 
Did you adjust up the pads to the discs? Just refitting the calipers without doing that will give the problems you have got.
 
You need to manually operate the handbrake quadrants to move the pad up closer to the disc, ideally by removing the disc, then operating the quadrants sliding the disc in every so often until it just slides in nicely with no excess space between the pads and discs, but not so tight that it binds. You can do it without removing the disc, but the end result will never be quite as good as if you do. You could also cheat and achieve nearly the same result by sliding the outer pads in and out. But without doubt the best results are obtained by doing it with the disc. Once it's set, then you need to make sure the quadrants are both back on their stops when the handbrake is off.
 
OK... I'm going to take a deep breath, have a strong cup of coffee, then proceed to the garage. Watch this space...
 
Also as an aside those hand brake pawls are in there correct position and not fallen over?

Graeme
 
Good question Graeme, and one I'll check up on tomorrow. Things were getting beyond my ken, so I limped the car around to John the mechanic, and he popped it up on the hoist for a closer look. He set the pistons as the Rover manual and the instructions in the Girling kits said, but I found the gap wasn't big enough for the discs and the pads, so I gave the pistons one more turn. So far as I could tell, the levers wouldn't turn on the pistons, so to get them upright I gave the pistons one full turn each. This allowed me to get the pads and discs in place, with a gap that a gnat could barely fit his knob into, but John thinks it might have been too much. He ran out of time today, but he's meeting me at his workshop at 8am tomorrow (Sunday, eeerrrrk!) for more investigation. He intends to lift the dust covers off the calipers and take a look at the adjustment from within there.

At the moment, the piston moves OK when the handbrake quadrant is manually tweaked, but not until nearly the end of the quadrant's travel.

It looks my self-imposed deadline of a WOF by tomorrow afternoon's company Christmas picnic (allowing me to take the family along in style!) is going to be missed, and I'll have yet another bill to pay. But such is life, and we have to persevere. I was getting a little despondent again today, being stymied by my brakes and having copped an eyeful of all the other little jobs that need doing on the car, but the drive around to John's (albeit slow and careful with only front brakes) reminded me of why I love the Rover P6. That effortless glide along the road, the gentle throb of the V8: you guys will know exactly what I mean. It beats the pants off my 2009 Toyota when it comes to the behind-the-wheel experience. No mean thing for a 40-year-old car.
 
when it came time to do mine I gladly sent it off to Chris B, the cost for a full rebuild was less than 400 bux including 2nd hand replacement disc and new pipes and flexi hoses, luckily the calipers already had stainless sleeves and the pads had bugger all wear.

graeme
 
WarrenL said:
At the moment, the piston moves OK when the handbrake quadrant is manually tweaked, but not until nearly the end of the quadrant's travel.
Click to expand...

Possibly because it hasn't been set up correctly initially I would imagine. Drop the discs, remove the handbrake linkage retaining pins and unbolt the linkage from the diff and move it out of the way, then ratchet the calipers up manually until the discs just slide in at rest. They should be ratcheting up properly, as they should have been bench tested before they were fitted.

I seem to remember having experienced exactly these symptoms very recently on a set of newly fitted calipers, and once the above procedure was carried out by someone who knew what they were doing, it ended up with a splendid handbrake. (Don't worry, I'm bound by Roverocratic Oath to keep all matters between customer and spannerman confidential, so your secrets are safe with me. You know who you are!!!! :LOL: )

Forget wasting time removing the dust covers in-situ, it wont be easy, and if the calipers aren't ratcheting up properly it's likely they'll have to be removed to sort the problem anyway.
 
Thanks Harvey, great reply. But just to clarify for the knows-enough-to-be-dangerous-and-no-more dummy here, could you please clarify the means of ratcheting up the caliper?

Cheers.
 
WarrenL said:
could you please clarify the means of ratcheting up the caliper?
Click to expand...

Operating the handbrake quadrant lever over its full travel (many times) which will gradually move out the pad operating piston. If you overdo it so much that the disc won't slide in, then wind the piston back in one turn, and repeat the process.
 
Cool, Harvey. I'm off to John's workshop now, where GF148 is currently lodged on top of a hoist. I'll report back later.

Thanks again everybody.
 
OK! It's all over. GF148 now has rear brakes. John had delegated the reassembly of the calipers to his offsider, who let Team Rover down by getting things not quite right inside. To allow Tony a little mitigation, it turns out that the two calipers were different inside, in slight but important ways. Are the experts here aware of different stud and sleeve types in the Girling calipers? In a nutshell, the pawls would not engage the pushrod teeth correctly, and no auto-adjustment was taking place.

John spent five hours (with my help) removing, stripping, correcting, testing, remounting and retesting the calipers, then flushing the brake system and adjusting the handbrake - all on a Sunday. And, with the exception of the time spent flushing etc, at no charge to me, for, as John pointed out, the calipers should have been done correctly in the first place. A marvellous effort that saw the old girl not only going, but stopping as well. With an afternoon Xmas party to make, I stopped by the WOF shop in an effort to travel there by Rover (and complete my previously stated goal), but unfortunately there was at least an hour's backlog and I had no time left. I had to abandon the Rover in favour of loading the family into the Toyota estate.

I was thoroughly over the Rover by the time I had it back in the garage - it's been a hell of a weekend, and I have the beaten up and blackened hands to show for it. However I'll be feeling a little more Roverly inclined by this coming Saturday, when once again I'll trundle her down the road and try for a WOF.

Tell me again why we do this to ourselves?
 
WarrenL said:
it turns out that the two calipers were different inside, in slight but important ways. Are the experts here aware of different stud and sleeve types in the Girling calipers? In a nutshell, the pawls would not engage the pushrod teeth correctly, and no auto-adjustment was taking place.
Click to expand...

Yes, and it has been covered on here before. IIRC the book only shows the early type with the sleeves over the studs. All easily converted to the later spec with the right parts. Regardless of who put them together, if they had been bench tested by the person who fitted them he would have found out they weren't working before they went on, If you're doing them for a living never trust anyone but yourself. That said, he's done right by you and got it sorted properly.
 
John was rather unhappy about the f***up yesterday. Tony the offsider works for him on an hourly contract basis - John says Tony owes him a few hours now. But it's great that there's still a mechanic out there who will stand by his work and see you right. I've so often come across the other sort.

Anyhow, all's well that ends well, and the brakes are working very well now.
 
Hi just come across this as I'm having similair trouble, but only on one side.

The calipers have been fully reconditioned by a very competent person (no, not me!), and one side is fine, but the passenger side doesn't seem to be doing much at all.

Is the "quadrent" the round washer type piece with the stops on it (held in by a slotted screw)? The one on the working side is moving quite freely, while the other side moves but doesn't always return to it's start position. Any ideas? I'll try again tomorrow, also, I know the bias spring is missing, what effect would this have on proceedings?
 
redhouse53 said:
Is the "quadrent" the round washer type piece with the stops on it (held in by a slotted screw)?
Click to expand...


That's what I would call it, although that's not necessarily what it's called in the book.

You should check that the return spring for the quadrant on the faulty caliper is fitted correctly, then decide whether the caliper is not working, or has been incorrectly set when fitted.
 
thanks harvey, got it all sorted today, pulled the h/brake mechanism off and checked it was all ok, adlusted the callipers, re-assembled (remembering the bias spring and hey presto, it all works. I'll fill up the fluid tomorrow and see if the foot brakes work too!
 
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