Hello. I'm in the UK. No experienced mechanics. no dealers difficulty getting parts. 2000 5.2 Van pulls to right on heavy braking then goes straight.... Does not do it with light braking. Front calipers and pads fine. What shall I try next? Rear brakes, master cylinder, ABS sensor, air suspension, shock absorbers, spring or something else.

 

If the RR brake is grabbing or the LR brake isn't grabbing enough you will feel a pull to the right. If it's a hard pull felt in the steering wheel that usually means it's the front brakes, a more mild pull means it's the back brakes.

 

Thanks. It is a hard pull to the right on braking but once corrected by steering left braking is then straight. Puzzling....

 

You're positive the caliper is not sticking?

 

I agree with potentshadow's question. I had a not too old set of calipers on my van, last summer the 30 mile drive to work in the cool of the morning was fine, but in the afternoon heat was not. about 7-8 miles on the highway the steering wheel would begin to shake and pull hard right. First day I stopped and just did a quick check around, then decided to take it one more exit, it rolled just fine rest of the way home. Next day again was fine in the morning drive but afternoon did the shake and pull again in nearly the same spot. Again I stopped and this time felt the hub and wheels and found my right front was pretty darned hot, so waited a short time and headed home like the previous day and went fine.
I pulled the wheel and caliper once home and didn't find anything looking too bad except the caliper was a bit tough to compress to get it off. I went ahead and pulled the other side and was a breeze to get the piston to compress. Went to napa and picked up another caliper for the right and installed the next morning. All was right in my world again.
If you haven't replaced the rubber flex line to the caliper or don't know if it has been, this would be a good preventative thing to do as well as a good time to do it while the caliper is off (if infact it is a sticking caliper) don't neglect to replace the other side flex line too, they deteriorate from the inside over time

 

You could take your Van to a MOT testing centre, and have your brakes checked on rollers. Or, find a lenght of dirt road and make low speed brakings and see which tire grabs least.

 

Thanks HeikIlm, JFloors and potentshadow. You are correct. I don't know if its a caliper or which wheel it is. Its going on a rolling road on Monday.

 

I would look at replacing the brake hoses. They fail internally and restrict fluid flow.