Brakes: I've Got That Sinking Feeling

[Drewski]

'Managed to sort out my front binding brake but now my brake pedal is spongy
I've read the thread about "sinking pedal" so 'will try back-bleeding the system, see if that helps. The pedal is hard with the engine off and sinking completely and slowly with it running. No signs of any leaks. '
Any other known solution apart from T4 bleeding? I have a lot of miles to cover with full loads and trailer loads soon as I clear out my old mans place and need the old girl in fine fettle.
Finding the correct brake parts was a bit of a struggle, 'ended up with the wrong type of cylinder seal and had to use the old tapered one - again. Just couldn't get the piston in with the new one.
Old tapered one
https://photos.google.com/photo/AF1Q...X8uqWZ7Tfwe9me
New nonsense one:-
https://photos.google.com/photo/AF1Q...KXMcGsQciGi2p6

[xsport]

Your pedal if pumped up and held before starting , should then drop once starting.This usually indicates that the servo is working. Im not sure about the diesel models as i have the KV6, but what i do know is that this has been a long time enigma for years especially on the automatics on petrol.not sure about the diesels , but im certain someone will be along to advise as the diesels have a different vacuum system .

[Drewski]

Originally Posted by xsport

Your pedal if pumped up and held before starting , should then drop once starting.This usually indicates that the servo is working. Im not sure about the diesel models as i have the KV6, but what i do know is that this has been a long time enigma for years especially on the automatics on petrol.not sure about the diesels , but im certain someone will be along to advise as the diesels have a different vacuum system .

Thx for that, I'll give it a try in the morning.

[Drewski]

Just had a quick look and when sucking with a syringe from the bleed nipple, hardly anything's coming out so I presume there's a blockage. I used a clamp on the hose, (I know), so it may be damaged, that or the caliper has some crud blocking the bleed hole. Ordered new hoses.

[Drewski]

Trying to catch up with this, just reading another thread that the brake pedal will sink, it's normal. Before servicing this caliper, I remember that the pedal sank slightly when starting the car, (auto), I noticed it a while back. It's now sinking a lot more but is that because I'm not starting the car straight away?
Something else - while the 75 was off the road waiting to get the rear arms replaced, I bought a cheap little Manual Japanese sports car. I wonder if I'm just getting used to the brakes on that and that has made me notice the sinking pedal more. Oh dear, I'm well confused Next step is to try the Rover 'round the block I guess

[Arctic]

Hi Drew.
There is no need to clamp the brake hose when changing a caliper, no good to you now, but al that is needed is before you start the job is to wedge the brake pedal down with a length of wood from the front seat to the pedal.

This stops any fluid coming out of the brake hose once it is removed from the caliper.

Have you checked the vacuum hose from the EGR to the valve that goes to the servo has not chaffed.

If that is ok i would bleed the caliper again, getting some one to press and hold the pedal down each time you bleed the nipple.

https://www.the75andztclub.co.uk/for...8&postcount=87

Try this
https://www.the75andztclub.co.uk/for...&postcount=116

read this thread from the beginning it's interesting and may help
https://www.the75andztclub.co.uk/for...=63314&page=13

[Drewski]

Hiya Steve,

Driving me nuts and couldn't be at a worse time. the brakes were all working fine then I had the rear arms done and a bit later noticed the front left was binding, very badly. I put a new piston in the caliper and bled the brakes by sucking the fluid through with a syringe. If I hadn't read the posts on here I would have thought that using the syringe may have damaged something, ABS? M/C? I must have bled each wheel about 4 times now, (but not yet the traditional way!), but I don't know anyone at my Dads to pump the pedal for me, the flow is really bad, esp when I tried Juless' method of pumping up to the M/C, like it's blocked somewhere. The old original fluid needed doing long time ago, that's why the brakes have been binding I think, rusty pistons. My bad, that one.
Hospital gave me 1 hours notice this morning that my Dad was been ambulanced to his new home in Cambridge so I'm down there now for a couple of days at least and the Rover's still in Sutton.
Just got in and need some nourishment, will add any more info in a bit....

[rrobson]

The backs were very tricky to bleed on mine. Changed a couple of calipers recently and I found fronts were fine after a quick bleed, but the back two needed repeat visits to clear all the air. Only a couple of tiny bubbles appeared after a flush of maybe half a litre of fluid but that was enough to stiffen the pedal. I did mine with a pressure bleeder but I’ve had much more success using the traditional two man pedal pressing method. This seems to clear the air quicker.

[Drewski]

Originally Posted by rrobson

I did mine with a pressure bleeder but I’ve had much more success using the traditional two man pedal pressing method. This seems to clear the air quicker.

Cheers, going to ask my Dads neighbour, I'm sure he'll assist, he likes his cars. 'Thought I'd be clever and do it on my own this time
Here's hoping.

[Drewski]

Originally Posted by Arctic

Hi Drew.


Have you checked the vacuum hose from the EGR to the valve that goes to the servo has not chaffed.

Steve, the pedal is hard with the car not running, from what I've read, this means the servo is ok. Is that right?

As far as I know the car has always dropped on the pedal a short distance on start up - if I start with my foot on the brake, it goes down a little. I understand this as the servo kicking in. However, I do remember first noticing this and I'd had the car a while then, plus the saloon before. unsure if it always did it and I just never noticed or not.