steveshone

steveshone

Member
Hi all, my p38 2.5 has brake problem, pulling hard to o/s when braking, all new ball joints and bushes throughout , new discs and pads all round, new front callipers, new front flexi hoses, rear calliper and slides free and working, the system has been bled with fresh fluid as per rave bleeding procedure, tyre pressures are what they should be, I have tried changing wheels front to rear, nothing so far has eliminated the problem. I am starting to suspect an issue with the brake master cylinder assy, and have thought of removing front prop shaft to allow me to get the car roller brake tested to locate any issue, any thoughts on this would be appreciated
 
steveshone said:
Hi all, my p38 2.5 has brake problem, pulling hard to o/s when braking, all new ball joints and bushes throughout , new discs and pads all round, new front callipers, new front flexi hoses, rear calliper and slides free and working, the system has been bled with fresh fluid as per rave bleeding procedure, tyre pressures are what they should be, I have tried changing wheels front to rear, nothing so far has eliminated the problem. I am starting to suspect an issue with the brake master cylinder assy, and have thought of removing front prop shaft to allow me to get the car roller brake tested to locate any issue, any thoughts on this would be appreciated
Click to expand...
No need to remove the propshaft if the brake test rollers can test 4×4's did you do the work on the brakes? Check you or someone else haven't left a hose clamp on the N/S flexi.
 
tomcat59alan said:
No need to remove the propshaft if the brake test rollers can test 4×4's did you do the work on the brakes? Check you or someone else haven't left a hose clamp on the N/S flexi.
Click to expand...
And bleed the NS again, to be sure.
Lift the front off the ground and wedge the brake pedal, check the brakes are coming on, both sides
 
I did the work myself no clamps left on flexi hoses, and it has been bled twice as per rave I am happy and confident its air free I may be wrong but the master cylinder assy is also abs unit containing solenoid valves, I'm wondering if the valve relating to the nearside front is not holding the pressure, I am toying with swapping the brake lines relating to the near side and offside front were they exit the master cylinder to see if it pulls the opposite way which would confirm an issue in the master cylinder/abs unit?. I do have testbook t4 mobile which may have diagnosed an issue but I lent it to a guy and his young son ejected the software disc and his jack Russell did a bit of doggy diagnostics with it in the garden with it!! , so if anyone can possibly help me with a replacement disc I would be ever so appreciative
 
I'd be looking towards the rear brakes.
Was the anything odd when you replaced the pads on the rear.
A caliper that had taken a little more force to return the piston?
 
steveshone said:
I did the work myself no clamps left on flexi hoses, and it has been bled twice as per rave I am happy and confident its air free I may be wrong but the master cylinder assy is also abs unit containing solenoid valves, I'm wondering if the valve relating to the nearside front is not holding the pressure, I am toying with swapping the brake lines relating to the near side and offside front were they exit the master cylinder to see if it pulls the opposite way which would confirm an issue in the master cylinder/abs unit?. I do have testbook t4 mobile which may have diagnosed an issue but I lent it to a guy and his young son ejected the software disc and his jack Russell did a bit of doggy diagnostics with it in the garden with it!! , so if anyone cwith an possibly help me with a replacement disc I would be ever so appreciative
Click to expand...
I had I guy come in the garage with your problem ,he had brake work done by another garage, when we put it on the ramp there was a clamp on the flexi we didn't charge him,kept the clamp and the customer. ;):D
 
hi, I have found no issue with the rear brakes, callipers and the slides. are in very good order with the corners jacked up and wife applying footbrake they ably and release with no binding, tonight I drove it at 20mph and applied light braking and the pulling could be felt, feels like throughout the braking range /effort the n/s front is getting less pressure and lower braking effort, everything brake related on the front is new. discs pads, callipers , carriers, flexi hoses. new discs and pads on rear, callipers and carriers are in good condition and free, all brake pipes are new cunifer copper, only thing not changed are rear flexi hoses but visually they appear very good, I think the two diagnostic options I have are remove front prop and have roller brake test and to swap brake pipes over n/s and o/s in master cylinder to try and make the car pull opposite way, and thanks to everyone for there input
 
I'd have thought guide pins or sticky piston on near-side. As far as I am aware the pressure into the modulator is the same for all lines but there is a solenoid for each brake line out in the modulator. I guess it is possible for one to fail or jam.

Was the bleed done as per rave?
 
hi, it was all bled to the letter of rave, rear slide pins and pistons free as they should be thank you for your input though
 
I wonder if the pistons in one of the new calipers is a bit sticky? Could try pushing out with an airline or a bike pump if you don't have one.

2 types of early modulator and then the later one after '99 with 4W TC. Those later models seem to suffer with ABS module (up behind the glove box) niggles. They're also massively more expensive!
 
From my experience, if a 'dry' caliper, ie new or rebuilt, doesn't have all the l pistons pushed fully home, you can bleed all you like and not get all the air out.
Make sure all the pistons are pushed as far into the caliper as they can go, then bleed that caliper again
Just a thought
 
sorry its been a while with regard to the issue I had with my severely pulling brakes the fault was the brake master cylinder unit, when trying to bleed the system I was not getting any fluid from one of the bleed nipples on the master cylinder. I fitted a replacement unit and the car pulls up perfectly, I can only assume one of the internal valves or solenoids had failed, thanks to everyone who contributed there thoughts
 
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