front brake balance

[LES DAY]

[X(]My 944 2.7 1989 has just failed the MOT how dare it!! anyhow the brake balance was not correct 110 near side 190 drivers side. Ha! I know it'll be the caliper sticking or the pins rusty, so quick change of the pins and loosen the callipers off and bobs your aunty---NO> still the same. I ve only had the car 10mths and the previous owner put new pads on ONLY, concerning as the pistons are now pushed back in. Before I start changing the calipers and the hoses bit by £100 bit until I hit the problem, I'm a bit concerned about the ABS, Not sure how it functions and if this could contribute to my problem. PLEASE HELP.
P.S I refurbished the brakes on my 86 911 carrera which was cheaper to do than the 944 is that right?
Thanks Les

 

[Guest]

Sometimes glazing and contaminants will screw up the balance. Any chance of oil / fluids having got on the disks / pads?
Have you tried dressing the pads with a medium abrasive paper stapled to a flat piece of wood and then giving them a good wipe with meths - and then giving the disks a good wipe over with abrasive paper and meths?

I used to get the same problem with my racing kit car and found a good dressing and wipe over would often sort the problem.

 

[Hilux]

Bleed the brakes, might be air in there.

Check flexible hose, these can perish and `balloon` under pressure, if in doubt change them for braided ones.

Compare wear/thickness of both sets of pads, if one is worn more than the side you have trouble with then you have probably inherited the problem and it may be a sticky piston, air in system, badly grooved disc, badly warped disc, contaminated pad (use brake cleaner on it) or a leak further back down the line.

HTH

 

[944turboS]

If it is your flexi hoses Eurocarparts do the braided kits for the same money as OE rubber hoses & a forum search will bring up details of how to get a futher discount on all items bought from them.

 

[Indi9xx]

Your 2.7 has the same cast iron calipers as the earlier LUX 944.

The problem is often due to the cast iron calipers rusting and stopping 3 or 4 of the 5 moving parts of the caliper from moving.

The piston, rarely seizes up on these calipers... but not many people realise there are components in these calipers which should be free running.

1. Piston body... the piston body is the cast housing that the piston and bleed nipple are in... it should slide slightly within the caliper ring.

2. Caliper ring... this is the part which goes around the side and back of the piston body, and loops around the other side of the caliper. this should slide on the piston body slightly and the pad retainer should move freely on it.

3. Pad retainer... this is the big part which loops over the top of the caliper, its the lump that the two pad retaining pins go through... this should move freely on the caliper ring.

4. Pad retainer pins.. two of these hold the pads in place.. the pads should be able to slide on them...

Then of course you have the piston... which should slide inside the piston body.

If these points are not free moving, not only will you possibly have a brake inbalance, but also you will not get as much performance from your brakes as you should.

Its often a good idea to remove the pins, and then strip down the caliper into the 3 main components of ring, piston body and pad retainer... then descale the areas where the 3 components touch,, you will notice that there are nylon blocks on the pad retainer.. but often they are gummed up, and the parts of the piston body and ring will be rusty, causing it to bind or seize.. if you find this, do both front calipers, otherwise the lower performing side might start out performing the other side which will give you the oposite imbalance.

It could also be old brake fluid, or air within the system...

Another thing to look for, is worn out or unevenly worn disks... generally, if they have a lip on the outside edge, they are worn out.. you have about 3mm of permissable wear on the disks... when they are new they have a 1.5mm chamfer on each side of the disk... once the edge of the disk has worn square, you are down to tolerance, once you start getting a large lip on the disk, they are normally bellow tolerance, but measuring the thickness of the disk is the only way to be sure.. the thickness of the disk in itself does not cause a loss of performance, but if its worn unevenly, or if the pad is rubbing on the lip, then you will get an imbalance.