Soft Brake Pedal help.

[scott180gtb]

On to the next problem!

After a complete brake line/calliper/flexy replacement I'm still not happy with the feel of my brake pedal.

I have completely bled the system manually and I'm certain I've got no leaks.

The pedal just has to much travel before the pads bite.

I know that compared to new anchors 20 year old brakes are never going to bite like my e39 but I was hoping for a little more initial retardation.

What should I be looking at?

If I pump the pedal the bite point seems to rise a little.

Do I need to re bleed or should I replace the master/slave cylinder.

[daimlerman]

Bleed first.

I have found that the rear brakes can be 'playfull' and tricky to bleed all the air from the lines.

[chh137]

Pressure or vacuum bleeding is a better option, particularly on ABS sysyems.

[scott180gtb]

There is probably a lot of slack in the lever/rod system. Undo the lock nuts on either end of the rod and "lengthen" it to take up the play so the push rod into the master cylinder is just up against the piston.

Also, make sure the slides on the calipers are free/lubricated. If they sieze up, the calipers cannot centre themselves properly which leads to excessive gaps between pad/disc.

My slides are all lubed up and it's all new disks and pads.

I might power bleed and then adjust the rod.

Should the rod ever need to be adjusted. If I remember they are quite meaty.
I'm just curious as to why the rod would go out of calibration.

I don't want to adjust anything that will mask a weak servo etc.

[daimlerman]

One symptom of the rod linkage being out of adjustment is flickering/always on brake lights/brake lights not working as the switch has failed due to the rod being out of adjustment.....bear in mind that one end(servo I think)has a l/h thread.

[Brianmoooore]

The rod does need to be adjusted over time. The leverage ratios are quite high, and there are several pivot points involved. Slight wear in each of these adds up to drop the pedal considerably, giving short pedal travel and eventually killing the brake light switch.

[scott180gtb]

Right the last push before the mot.

What type of power bleeder is best suited. There is so many to choose from?

http://www.ebay.co.uk/itm/Hand-Held-Vac ... 4164c31265

[daimlerman]

That looks a bit posh!

I use a Gunson easy bleeder,it uses air pressure from a spare wheel set at about 20PSI.

[scott180gtb]

Sorted this. I ended up with the easy bleed Malc as it was the only bleeder I could get hold of in York.

I bled the whole system again. I couldn't see any air bubbles come out but I now have zero travel in the pedal and good retardation/bite early in the stroke.

Also passed the mot.

[Andyboy]

I use a Gunsons easy bleed, pressure from a spare wheel but not too much! Cover the maaster cylinder reservoir with a wet towel, just in case.
E30's with ABS can be a sod to bleed up so make sure the ignition is on. With regard to the pushrod, the idea is that you raise the pedal height. With the 17mm nuts slackered (one is a reverse thread) you use an 8mm spanner on the rods' 'flats' to wind it out and you'll see the pedal raising. Often it's the only way to restore a good pedal feel. Don't overdo it because if you do, the brakes will start to bind on as the brake fluid warms up.