TR2/3/3A tr3 front brake pulling

[sp53]

On a tr3 when a front brake pulls, does that mean that one of the pistons in the caliper is not working properly and the wheel is thrown over onto a more relaxed piston? The reason I am asking is I just can not see the problem. I have new pads and freshly turned rotors(maybe 5000miles) and when I was on a driver and when I first hit the brakes at 70/60 mph the car would pull to the right kinda hard, but after the first hit the brakes would improve some and not pull so much to the right . Does anyone have a suggestion?
Sp53

 

[DougF]

Are your flexible rubber hoses in good condition? If you don't know for certain, I'd replace them all around. You can't give them an outside visual inspection because they will swell internally, blocking the passage. You almost have to disconnect the line and watch the flow while somebody presses the pedal.
If not the hoses, inspect the calipers and work your way up through the system.

 

[MGTF1250Dave]

My suggestion is that one or both pistons on the left side are hanging up. The right hand brake is doing most of the work and drags the car to that side. The pressure you developed during repeated braking is getting the left side pistons moving. This may be a result of some corrosion in the bore or on the piston and secondly the the rubber seal may have come out of the groove in the piston. Air in the system on that side is another possibility. Good luck.

Safety Fast,
Dave

 

[Alan_Myers]

Hi,

Dave is right, most likely it will be the pistons hanging up or sticking momentarily on the opposite side... I.e., if the car pulls to the right, take a look at the LH caliper.

In rare cases, it can be a problem on the same side though. This might occur if a pad has cracked or delaminated from its backing, or if a rotor has some sort of partial failure, either of which at least temporarily could cause an increase in friction effect and drag on that side (but signal a more complete failure to come).

Other possibilities do include the hoses (old rubber hoses can burst, rubber hoses in general give a softer pedal due to expansion than do braided stainless steel-type hoses... a good upgrade!)

Also there might be a problem with the pads, one or two not seated properly. Or it could be a brake fluid leak or oil has contaminated the pads on one side.

Any system leak might be hard to spot under the car, but would show up as a rapid drop of fluid level in the master cylinder reservoir.

Don't overlook the rear brake adjustment, either, although IMHO that's not as likely the cause.

Finally, many brake pads, rotors, shoes and drums need a careful break-in. For example, read the instructions that come with EBC Greenstuff pads very carefully. Various pads using different materails will each have their own break-in procedure. Failing to follow initial break-in procedure might heavily glaze pads on one side, causing an effect like you are seeing. It might mean replacing the pads, or be as simple as using a file or some sandpaper to remove the glaze on the pad, but do so with care.

Overall, this is such an important enough safety concern that I'd strongly suggest you get a brake repair shop involved if you don't find an obvious solution quickly.

/ubbthreads/images/graemlins/cheers.gif

 

[Geo Hahn]

Probably not your problem...

...but to just eliminate a simple thing: confirm your tires are properly inflated. A slow leak in a front tire can create a difference in pressure left-to-right that will cause a pull under hard braking.

 

[sp53]

Thanks all for your input, good sound advice. I am going to check the left side for air first to see if that could be the problem. Sometimes I get so inside my own head that I can not envision the problem. Initially, what I was going to do was start on the right side and perhaps rebuild the caliper there. In the end I will probably rebuild them both. However, they were rebuilt about 14 years ago. Moreover, I did check the fluid level and it was good. I guess often what it is with me is, I like to understand the problem. I have this kinda cat and mouse relationship with faulty parts. They break and I try and figure out how come and why. Keeps me sane and out of trouble.

Thanks all.
Sp53