Long brake peddle

[Silverfox58]

Hi all I have a long brake peddle, I have good brake pads, if I pump it once it's ok ,but have to do this each time
I brake, Any ideas

[X5Sport]

Pads not moving back due to distorted discs? That would create extra room you need to push the pads back into place before they work properly.

Fluid level not falling? Leak and so you need to push more fluid in.

Fluid replaced and system bled within the last two years? Fluid absorbs water and gets gas bubbles.

Air in the system? As above. Old fluid can get bubbles in it.

Just trying to think of a few items that might cause this. Loss of the servo would make the pedal very stiff. Might be a seal issue in the master cylinder - does the pedal ‘drop’ if you keep your foot on it with a lot of pressure but not with gently pressure (might show a bad seal on the piston in the master cylinder allowing fluid past.

[Silverfox58]

Hi x5
I haven't changed the fluid, so could be that , it hasn't lost any fluid, I will have to try the pedal and see what happens , will let you know.

[henrym3]

Having been there so to speak, my money is on the beginning of brake line failure and although you haven’t lost fluid yet you will be soon. I would make it a matter of priority to inspect your brake lines, especially behind the front left wheel arch. That means taking the wheel arch off.

[Silverfox58]

Ok thanks will do

[Silverfox58]

Ok as I have been working away but home this weekend I thought I would look at the brakes,
Lines are ok nut a bit rusty but look ok , so I thought I would change the master cylinder, done that but trying to
Bleed the brakes I have found the the rear calipers are seized so that could be the problem so just ordered a set and brake lines all round as I'm off next weekend, thats my weekend sorted.

[henrym3]

Did you buy all the lines front to rear of BMW. You can get a calliper repair kit of e-bay as callipers are probably very expensive. The problem is you need to dismantle first to see if they are repairable.. Good luck with replacing the lines, the ones under the rear subframe which will be well rusty won’t be an easy job. Might I recommend that while you have a lot of the trim off underneath that you think about doing the fuel filter so you don’t have to revisit.

[Silverfox58]

Thanks for your advice, that was going to be my next question, what do I have to take off ,and is it just the left hand side plastic work.

[henrym3]

Yes all the lines run down the left side, which necessitates removing about 1 million screws (slight exaggeration) including the wheel trim. I had the rear subframe off for bead blasting and powder coating so for me the brake lines were easy and I used copper piping. With subframe fitted I would imagine it would be considerably more difficult
You will probably need a diagnostics tool to cycle the ABS pump to bleed.

[Silverfox58]

So what's this tool for the abs pump ????

[henrym3]

You can do it with INPA or some of the Foxwell tools ie the 510/520 and others. I didn’t use any of them, I used patience??

6FADF015-AF02-454C-8234-48C761977E77.jpeg (366.98 KiB) Viewed 3939 times

99396878-2C8A-47C2-B847-CBA61BAC6995.jpeg (321.52 KiB) Viewed 3939 times

These pics show the intermediate pieces which join the lines together. Instead of a line one has a bleed nipple screwed in. I attached a bleed tube put it in a bottle, made sure the reservoir was full, opened bleed and left it. One line took 15 mins, the other took 2 hours for fluid to appear. done up the nipple and had a solid pedal. By that time I had finished fitting the lines to the callipers so I removed the bleed screws and joined the lines together, put the bleed tube on the Caliper and repeated.

[Silverfox58]

Ok that's great and thanks for your advice, I will let you know how I get on

[sleepyfolk]

I also replaced all the fixed steel brake lines with copper due to bad corrosion, once you pull the plastic off you might find a horror show, front off side was weeping but not enough to drain the reservoir quickly - as soon as it was moved it split so I was lucky really.

The lines from the ABS run up into the front nearside wheel arch and behind the plastic all the way to the back so you need to drop that as Henry says - which you can do without too much trouble but I’d definitely order some new clips and rivets as there’s bound to be some that break. They tend to rust around the plastic clip that holds the lines to the floor which can’t be seen.

The lateral line that runs over the top of the sub frame is very difficult to see and replace - we dropped the subframe on mine - you can see where the fixed line disappears on my photo up over the rear bush - gave me the chance to refurb the rear diff seal and give it a lick of paint - every cloud!

[Silverfox58]

Well it looks like it going to be a mammoth job, especial as I don't have a ramp and will be doing it of axle stands .

[henrym3]

Yes a fairly hefty job, but unlikely ever to need to do it again, I’ll bet you will be glad you did it when you get all the old pipes off and see the condition in places.