Bleeding brakes

Post Sat Jun 13, 2015 9:37 am

Hi guys
I've bled brakes hundreds of times before including full fluid flushes and even empty systems but this is being a pain, I have a 89 325i sport and I've fitted the e32 MC and servo to it along with e34 540i front Calipers (I have the rears to go on but haven't done it yet)
Filled the MC to the brim and cracked off all the nipples to let it bleed through a bit as its had no fluid in for quite a while, well I get fluid at the front two Calipers but the problem is the rear

The osr Caliper doesn't get any fluid even when pedal held down then nipple cracked off, the nsr Caliper bled a little bit but not normal amount of fluid coming out, I cracked the lines to the trailing arms to check if I had a blockage in the nsr Caliper and no fluid there either

When I first started bleeding the pedal was soft but now it's rock solid and won't move far at all

Googling all last night and this morning and I can only point it to a blockage,faulty MC or the abs pump? I hope it's just the abs pump has air in it as its been sat for a long time with no fluid in it and supposedly it needs to be cycled to help bleed it, I can only find very vague guides on this so does anyone have any ideas?i can't take it to bmw as she's still in bits

It's doing my head in, I was on course for getting her ready for mot and this has thrown me off

Thanks guys

Post Sat Jun 13, 2015 9:51 am

If you have air in it the pedal will be spongey, not hard, you need to keep working back from the rear, so next connection is the T piece, then the pressure valve under the servo etc. Ive bled loads of systems with ABS pumps that have been dry and off the car and never had to do anything special to bleed them

Post Sat Jun 13, 2015 9:54 am

I bet the bleed nipple is blocked, you could crack the join at the rear where the caliper flexi pipe joins and see if fluid dribbles out.

Post Sat Jun 13, 2015 10:08 am

I cracked the flexi/Caliper connection
Nothing came out that's why I went to trailing arm connection as it looked the least corroded

I did have the hard line that connects to the bias valve under the servo off as I took the fuel pipes and that brake pipe off to do some welding repairs but that's back on and right
I'll crack it off and see if I have fluid there

There's no interior in the car at the moment and as I was pumping the pedal I could hear fluid moving about so I just hope that the servo isn't full of fluid
I don't think it is cos the level in the res hasn't changed

I know there's air in it cos some came out the other rear Caliper followed by a tiny trickle of fluid