2008 ML 320Cdi Pulling to the right under braking

[PaulMason]

Hi all, wonder if anyone can make a suggestion as to potential causes to investigate. Last year whilst in France on holiday, the ML started pulling to the right on braking and by the end of the holiday (and c. 2k miles) had a bad judder too. Changed the discs, pads, guides pins etc and cleaned up the carriers with a wire wheel. The drivers side was a nightmare to remove the disc and involved a lot of heat and a big hammer. But, problem solved. However, it's started pulling to the right again (after about another 6k miles). Today I changed both calipers (cracking deal from Halfords, refurbished calipers with MB and ATE markings in a pagid box for only £98 each) and new guides pins. The calipers removed, particularly the near side seemed to have a seized lower piston. All bled and working fine, but still pulling a little to the right but much less severe (only on the brakes not pulling normally)? Anyone got any ideas why? I am going to go to the local MOT station and ask if for a small fee I can use their brake rollers but wondering if anyone has experienced anything similar? Could a sticky rear caliper cause this?

 

[W1ghty]

Is the cars tracking/alignment ok ?
The judder under braking if it comes through the steering wheel might be wear in the front control arms rather than brake issues (assuming everything has been done correctly) .What is the cars mileage if it’s on original front suspension parts ?
If the judder feels through the seat , then yes it could be the rear braking system ?
I’m sure any garage can quickly identify brake/piston issues .

 

[PaulMason]

Sorry, the judder was from the previous set of discs I changed. Not currently juddering, just still pulling slightly. Car has 136k on it and it does have a rattle from the nearside which I am thinking is the lower ball joint but a pretty big and expensive job to replace as believe it's driveshaft out and a new bearing too (plus the cost of the lower control arm)

 

[PaulMason]

Tracking was done last year so think that's all in order too

 

[W1ghty]

Sorry, the judder was from the previous set of discs I changed. Not currently juddering, just still pulling slightly. Car has 136k on it and it does have a rattle from the nearside which I am thinking is the lower ball joint but a pretty big and expensive job to replace as believe it's driveshaft out and a new bearing too (plus the cost of the lower control arm)

Might be just worn bushes/joints at that mileage , it’s a big heavy car .
The lower ball joint and suspension arm on my E class was straightforward, I’ll take your word that the driveshaft needs removing to do the job .
Lemforder parts from AUTODOC would lower the parts cost substantially.

 

[W1ghty]

Tyre pressures ?
Worn mismatched tyres ?
Broken front suspension spring or worn shock absorber ?

 

[PaulMason]

I did the tyre pressures and it's on airmatic so not broken springs. Not sure of shock health?. I will at some stage have to have the bottoms arms etc done, but likely use a local indie as looks complex and doing it on the drive on axel stands.ay be a bit of hobbying too far

 

[PaulMason]

Thanks for all the ideas though W1ghty

 

[W1ghty]

Thanks for all the ideas though W1ghty

Hopefully someone who knows something will weigh in soon

 

[PaulMason]

Hopefully someone who knows something will weigh in soon

You were right W1ghty!! So whilst the calipers were sticky and needed changing (now done all 4) looks like the ultimate cause was indeed the suspension (my bottom arms were "very very well used" according to the indie who did them). I had been meaning to get the front lower arms and ball joints done since flagged on last MOT, but have been putting it off as it's a big job and I didn't want to do it myself. Now have had it done and, Hey Presto, looks like the issue is resolved! The MB whisperer W1ghty had it spot on all along. As an added bonus, no more rattles and clocks, car feels more solid and now actually drives straight