Rear Axle End Float??

[OldManGhia]

I have had an on going problem for the past 5 years with poor brake peddle pressure. The brakes have been bled numerous times, master cylinder, booster, and now the front calipers have all been replaced. I have also had a problem with the hand brake requiring adjustment 2 to 3 times a year.

The car was at the mechanics this week for the annual rego inspection and he was not able to adjust the hand brake sufficiently. He did find that the rear axle end float (about 1 mil or so) was excessive and blames this for the poor hand brake adjustment. He has also suggested that this may be the cause of the brake problem. His theory is that the rotor is pushing the pads away as the axle moves out and when I use the brakes the pads have to be pushed back against the rotor before there is any brake pressure. He also said that the local bloke who repairs the diff housing has done about 40 of them mostly AU for the local Ford Dealer. Because my diff is not noisy a proper repair should cost around $900. But if the diff was noisy $1500-2000. The cheapest way to fix it is to replace the wheel bearings and use a spacer to take up any remaining movement.

Has anybody else experienced anything like this or have any suggestions??

[OldManGhia]

Somebody must have some thoughts or whatever about this problem...

Thanks guys

[sly]

The brake and handbrake issues you describe sound like the typical experience of Series 1 AU owners. What exactly do you mean by poor pedal pressure though? My pedal was hard and lacking in feel, needing a good shove to get the brakes working, although the travel was short... felt like the brakes were underboosted.

Do you have a lot of freeplay in the pedal... it goes down a long way before offering any resistance or there is any hint of slowing? If so, 2 things come to mind...

1. Maybe there is excessive clearance between the booster pushrod and master cylinder piston. The pushrod has an adjuster screw that can be screwed out to close the gap.

2. Was the master cylinder bled (rather than bleeding at the wheels)? I've heard of air being trapped in the master cylinder, requiring a specific bleeding technique... jacking the rear of the car up until the master cylinder bore is horizontal, disconnecting the brake lines (one at a time????) and inserting a bleed tube in their place, then pumping the pedal to force air out.

I'm a bit sceptical about the axle end float affecting the brakes that much, but it's probably something you need to fix anyway.

[mik]

its possible it still has air in it (i would put my money on it), also it is possible to have a faulty master cylander specially if its was a reco(but it does`nt happen often, spongey pedal can also be soft brake hoses braided brake hoses is a good upgrade anyway, his theory on the hand brake doesnt seem right to me, but without having a look who knows, maybe get a 2nd opinion?

[OldManGhia]

Thankyou for the replys.

The pedal on a good day has little movement before the brakes start working. The pedal feels firm and braking is quite good (for an AU anyway). But on a bad day the pedal will go as much as half way before there is any pressure at all. The brakes still work but just lots of pedal. If you take your foot off the brakes then re-apply the brakes straight away you have a full pedal and good brakes. At least until you go to use it again. Them the same thing happens.

As mentioned before the brakes have been bled at least five or six times. There was no difference between the old master cylinder and the re-built one.

[atec77]

Originally Posted by AU98C-Wagon

I have had an on going problem for the past 5 years with poor brake peddle pressure. The brakes have been bled numerous times, master cylinder, booster, and now the front calipers have all been replaced. I have also had a problem with the hand brake requiring adjustment 2 to 3 times a year.

The car was at the mechanics this week for the annual rego inspection and he was not able to adjust the hand brake sufficiently. He did find that the rear axle end float (about 1 mil or so) was excessive and blames this for the poor hand brake adjustment. He has also suggested that this may be the cause of the brake problem. His theory is that the rotor is pushing the pads away as the axle moves out and when I use the brakes the pads have to be pushed back against the rotor before there is any brake pressure. He also said that the local bloke who repairs the diff housing has done about 40 of them mostly AU for the local Ford Dealer. Because my diff is not noisy a proper repair should cost around $900. But if the diff was noisy $1500-2000. The cheapest way to fix it is to replace the wheel bearings and use a spacer to take up any remaining movement.

Has anybody else experienced anything like this or have any suggestions??

I doubt the end play is a real problem in the manner your " mechanic" claims , usually it's a pedal shudder easily solved by new bearings in the end tubes and some shimms , any competent diff bloke can do it for three hours labour and parts , the brakes however sound like leaky and or bad fliud , I would be checking and rebuilding/replacing slave/caliper seals and is the trouble persists a full fluid bleed and possibly master swap as well , for the couplf of hundred it will cost the safety aspect can't be over stated

[OldManGhia]

Originally Posted by atec77

I doubt the end play is a real problem in the manner your " mechanic" claims , usually it's a pedal shudder easily solved by new bearings in the end tubes and some shimms , any competent diff bloke can do it for three hours labour and parts , the brakes however sound like leaky and or bad fliud , I would be checking and rebuilding/replacing slave/caliper seals and is the trouble persists a full fluid bleed and possibly master swap as well , for the couplf of hundred it will cost the safety aspect can't be over stated

Master cylinder has been changed, front calipers reconned, brakes bled about six times and bled through a couple of times, booster exchanged, nothing done to rears though.

I have spoke to another mechanic about shims and new bearings but I wonder if that will make any difference to the brakes?

[cog]

This may sound stupid but are the brakes being bled using clear tubing? That way you can see if there is still air coming out as you bleed them. Also some bleeding techniques can cause dramas/leave/draw air back in if not done correctly...

[mik]

impressive 7 year thread mine .

[cog]

Haha, maybe should've read the dates...
Maybe should've been sleeping instead

[mik]

thats alright mate , we all get caught sometimes .

[mookie01]

Originally Posted by OldManGhia

I have had an on going problem for the past 5 years with poor brake peddle pressure. The brakes have been bled numerous times, master cylinder, booster, and now the front calipers have all been replaced. I have also had a problem with the hand brake requiring adjustment 2 to 3 times a year.

The car was at the mechanics this week for the annual rego inspection and he was not able to adjust the hand brake sufficiently. He did find that the rear axle end float (about 1 mil or so) was excessive and blames this for the poor hand brake adjustment. He has also suggested that this may be the cause of the brake problem. His theory is that the rotor is pushing the pads away as the axle moves out and when I use the brakes the pads have to be pushed back against the rotor before there is any brake pressure. He also said that the local bloke who repairs the diff housing has done about 40 of them mostly AU for the local Ford Dealer. Because my diff is not noisy a proper repair should cost around $900. But if the diff was noisy $1500-2000. The cheapest way to fix it is to replace the wheel bearings and use a spacer to take up any remaining movement.

Has anybody else experienced anything like this or have any suggestions??

sounds like somebody has machined the rotors at some point which i never do because the pedals go soft, do not machine rotors have them replaced with new ones it is just not worth it