83 SC - Brake issue: pulling to the right

[83_Silberpfeil]

For my 83 SC, I am experiencing the car pulling to the right when applying the brakes.

This is after I refreshed the brake system over the past few months.

- new pads, rotors
- calipers restored by Eric @ PMB
- new hard lines (attached to caliper)
- new rubber lines
- new fluid, bled out air

Two observations:

1) it seems to be more severe once the car is warmed up after a few miles of driving.
2) From visual inspection of the rotors/discs, only the front right/passenger disc showing circular marks. The other three rotors look barely touched by the pads.

It seems only front right caliper and pads are applying grip on the rotor.

After the brake project, with wheels mounted, and car still on stands, I rotated each wheel by hand/arm and applied brakes (by helper). Everything worked as expected, all 4 corners.

Where to start on this diagnosis - calipers/pistons, brake lines, MC, booster, vaccum?

Thanks!

[356911930]

I would try bleeding the whole system again first. Front left then front right then rear left then rear right.

Best of luck,

Rahl

[GH85Carrera]

Have you ever corner balanced the car?

A perfect alignment and best possible corner balance was the cure for my car. Actually mine did not pull to one side or the other much, but the right front would lock up under threshold braking. Always the right side. Alignment and corner balance fixed it.

If and suspension parts are worn, like a ball joint, or tie rod it can cause it as well.

[83_Silberpfeil]

Thanks Rahl! I am inclined to start somewhere along these lines. Low effort, low cost.

Curious about your suggestion to start at front, then the rears.

Originally Posted by 356911930

I would try bleeding the whole system again first. Front left then front right then rear left then rear right.

Best of luck,

Rahl

[83_Silberpfeil]

Appreciate your suggestion GH85Carrera.

Not under my ownership --- past 13 years, ~ 5K miles.

Suspension is likely original. The paperwork I inherited from previous owner did not show any suspension work done, stretching back to 2003 and about 20 K miles.

It certainly looks old, and could be worn. Feels worn during driving. Will keep this post and suggestions in mind. But, first will pursue less costly and less effort routes.

Originally Posted by GH85Carrera

Have you ever corner balanced the car?

A perfect alignment and best possible corner balance was the cure for my car. Actually mine did not pull to one side or the other much, but the right front would lock up under threshold braking. Always the right side. Alignment and corner balance fixed it.

If and suspension parts are worn, like a ball joint, or tie rod it can cause it as well.

[PeteKz]

Jonathan, these cars are very sensitive to corner balance and alignment. Try corner balancing first.

[GH85Carrera]

Originally Posted by 83_Silberpfeil

Appreciate your suggestion GH85Carrera.

Not under my ownership --- past 13 years, ~ 5K miles.

Suspension is likely original. The paperwork I inherited from previous owner did not show any suspension work done, stretching back to 2003 and about 20 K miles.

It certainly looks old, and could be worn. Feels worn during driving. Will keep this post and suggestions in mind. But, first will pursue less costly and less effort routes.

I understand the reluctance. It is a long and expensive process to refresh the suspension and lots of "well, while I am in there" project growth. The first choice is what do you want from the car. I wanted a car my wife would ride in, so a track focused suspension was never on the table. I think it is the perfect all around track or cross country cruiser.

I will never forget the gut punch I felt walking out into my garage and seeing my beloved 911 with no suspension and saying out loud, "Glen, what the F**k did you do" It all went back together and transformed the car. Now it is like a laser beam, move the steering wheel an millimeter, and it changes directions to where I want it to go.

The rubber bushings after 40 years have cold flowed, and worn out. Even a car with just 100 miles, those bushings are shot. Your torsion bars are likely rubbing.

Good luck with your 911. Drive it and enjoy it. Make it the car you want it to be.

[83_Silberpfeil]

Originally Posted by PeteKz

Jonathan, these cars are very sensitive to corner balance and alignment. Try corner balancing first.

Thanks for chiming in PeteKz, good to know about sensitivity of corner balance.

When I started driving the car again (before smog/registration), I didn't encounter this issue. So, corner balancing issue doesn't seem too likely to me at this point.

I noticed it only after I got my car back from the shop that worked on my car to resolve a number of items --- including: replacing the rubber brakelines on the passenger side front & rear. As part of that job, the shop also replaced brake fluid.

I will take fotos of all 4 rotors/discs and post here this weekend. It will show that only the front right/passenger side disc has the circular marks. Seems very odd to me that only one caliper/brake is working.

I should take the car back to the shop and have them take a closer look --- I plan on this in the future.

[83_Silberpfeil]

I had similar gut punch feeling when I put my car on jack stands, and removed all brake pads, rotors, hard/rubber lines, and front hubs. But, little by little, I restored, replaced each component and got it back together.

I sense it would be similar for refreshing the suspension. It would take a great commitment (time and money for parts) to do it myself. I am confident that I am capable --- but not sure I can commit to it at this moment.

Originally Posted by GH85Carrera

I understand the reluctance. It is a long and expensive process to refresh the suspension and lots of "well, while I am in there" project growth. The first choice is what do you want from the car. I wanted a car my wife would ride in, so a track focused suspension was never on the table. I think it is the perfect all around track or cross country cruiser.

I will never forget the gut punch I felt walking out into my garage and seeing my beloved 911 with no suspension and saying out loud, "Glen, what the F**k did you do" It all went back together and transformed the car. Now it is like a laser beam, move the steering wheel an millimeter, and it changes directions to where I want it to go.

The rubber bushings after 40 years have cold flowed, and worn out. Even a car with just 100 miles, those bushings are shot. Your torsion bars are likely rubbing.

Good luck with your 911. Drive it and enjoy it. Make it the car you want it to be.