Used my at weekend - after about 30 miles of mixed driving inc lots of stop start and no issues, pressed brake pedal and it almost went to the floor - quickly released and pressed again and pedal fine! it did it again after a couple of miles then fine. Not losing fluid, no other problems that I can make out - in the past couple of yeras has had new rear calipers and 1 front caliper and then about 1month ago got a new (reconditioned servo) ...no issues in the meantime...... thoughts please. The car is a 1970 auto 3500 :?
Pedal Drops almost to floor
- Thread starter lunarboy
- Start date
redrover
Well-Known Member
harveyp6 said:
That happened to me. Tap-tap-tapping noise coming from the OSF wheel at low speeds on the over-run. Disappeared when the brakes where applied. After a while, it got bad enough (although the sound never got worse) that the brake pedal would go almost to the floor. But once you let it back up again and applied the brakes again they were perfect. Apparently, it's called pad knock-off and affects disc-braked wheels. The play in the bearings causes the whole hub/disc assembly to wobble from side to side. When the disc hits the pads, it effectively pushes the pistons back into the caliper. When you go to apply the brakes, the first section of travel in the pedal is the fluid moving the pistons back out into contact with the pads and thence discs. The next push is the actual braking force.
Simple explanation and fix. Still bloody scary in practice....!
Michael
devilsplaymate
Member
HI.
I once had an issue similar to yours, and it turned out to be a duff master cylinder. Replacing the seals etc cured it.
Glen.
I once had an issue similar to yours, and it turned out to be a duff master cylinder. Replacing the seals etc cured it.
Glen.
Hello Lunarboy,
I too have experienced that very unsatisfactory situation of pushing on the brake pedal only to have to go straight to the floor, with no resistance at all and no application of the brakes. This was in 1986 or so and being new to driving a very unpleasant experience to say the least. Quickly releasing the pedal and pressing again they worked fine, almost as if I had just imagined having no brakes... :shock:
Having no experience with cars at that time I visited my local Rover dealership, and upon collection the Service manager said that the master cylinder had been at fault. He said something about valving... :? What ever he did the problem has never repeated and in the subsequent times when I have rebuilt the master cylinder I have never had any problems.
I know that the same problem had affected a number of other local Rovers too.
As Harvey advised, check the end float within your front wheel bearing so as to either rule them in or out, and depending on the outcome you can then look to the master cylinder if need be.
Ron.
I too have experienced that very unsatisfactory situation of pushing on the brake pedal only to have to go straight to the floor, with no resistance at all and no application of the brakes. This was in 1986 or so and being new to driving a very unpleasant experience to say the least. Quickly releasing the pedal and pressing again they worked fine, almost as if I had just imagined having no brakes... :shock:
Having no experience with cars at that time I visited my local Rover dealership, and upon collection the Service manager said that the master cylinder had been at fault. He said something about valving... :? What ever he did the problem has never repeated and in the subsequent times when I have rebuilt the master cylinder I have never had any problems.
I know that the same problem had affected a number of other local Rovers too.
As Harvey advised, check the end float within your front wheel bearing so as to either rule them in or out, and depending on the outcome you can then look to the master cylinder if need be.
Ron.
lukewilliam1_75
Member
I had the same problem within the last 2 months, took it to a local brake place, they pulled off the master said it didnt need to be sleeved, i just needed it to be re kitted and re sealed, all out for about 240 bucks if i remember correctly, and its as hard as a rock, more so then my new car!
Thomas-P6
Member
Hi,
I found this older thread when searching the forum because my 1975 3500 Auto just did the same thing last week on several instances during a spring holiday trip. It happened when doing local traffic as well as on long distance highway driving. The last instance was especially scary because I had to depress the pedal 3 times before pressure would be back. Luckily, this was shortly before we reached home base.
During the winter period I rebuilt the rear calipers and put new pads in, and the fluid reservoir was taken out and cleaned. After bleeding the system, the car passed the TÜV-Test with no problem. At the moment, I cannot state any loss of fluid, but I will pull out and check the master cylinder. Also will check if any fluid has gone into servo unit. Front wheel play is okay.
Can possibly lunarboy tell us if and how he solved his problem?
Thanks for your feed back.
Thomas
I found this older thread when searching the forum because my 1975 3500 Auto just did the same thing last week on several instances during a spring holiday trip. It happened when doing local traffic as well as on long distance highway driving. The last instance was especially scary because I had to depress the pedal 3 times before pressure would be back. Luckily, this was shortly before we reached home base.
During the winter period I rebuilt the rear calipers and put new pads in, and the fluid reservoir was taken out and cleaned. After bleeding the system, the car passed the TÜV-Test with no problem. At the moment, I cannot state any loss of fluid, but I will pull out and check the master cylinder. Also will check if any fluid has gone into servo unit. Front wheel play is okay.
Can possibly lunarboy tell us if and how he solved his problem?
Thanks for your feed back.
Thomas
Thomas-P6
Member
Brief update:
just pulled out the servo and dismantled it. There was about a good shot of liquid inside which poored out. In addition, the bottom inner side had some older jelly muck indicating that smaller amounts of liquid mus have gotten there over the years. So I suppose this is where my problem is. Waiting now for the repair kit to arrive to replace all seals and put it back together.
Thomas
just pulled out the servo and dismantled it. There was about a good shot of liquid inside which poored out. In addition, the bottom inner side had some older jelly muck indicating that smaller amounts of liquid mus have gotten there over the years. So I suppose this is where my problem is. Waiting now for the repair kit to arrive to replace all seals and put it back together.
Thomas
Thomas-P6
Member
Hi,
just wanted to report on my progress on this problem:
• I overhauled the servo unit, but the loss of brake pressure came back a day later
• fitted a new master cylinder: now it's okay, i did a 600 km trip on the weekend with no problems
(other than the engine stalling completely while being 500 km away from home, I'm opening another thread regarding this under V8-Engine, any help is much appreciated).
Thanks
Thomas
just wanted to report on my progress on this problem:
• I overhauled the servo unit, but the loss of brake pressure came back a day later
• fitted a new master cylinder: now it's okay, i did a 600 km trip on the weekend with no problems
(other than the engine stalling completely while being 500 km away from home, I'm opening another thread regarding this under V8-Engine, any help is much appreciated).
Thanks
Thomas