I have recently converted my 914 rear brakes to 911 ones. The changes were made from all the advice, threads, etc found on this site and 914club.com. I have been over the entire installation and everything seems in order and done correctly;

The problem relates to the left side rear e-brake shoes causing the rotor assembly not to rotate when everything is torqued down. The right side appears to rotate when torque is on the rotor. It appears the brake shoes are digging into the rotor when torque is applied. I do not notice any tracing of scaping anywhere on the inside of the rotor assembly. I am working on the idea that the clearance may be wrong such as brake shoes not arched properly, etc. These same shoes and rotors were used on the donating 911 so I am operating somewhat at a loss.

Any information and advice is greatly appreciated.

Steve Hurt
shoguneaagle

Is your hand brake on?

the cables are not hooked up; the problem appears involving the lateral clearances beteen the shoes and the rotor housing itself. I can adjust the shoes to any position and the problem still occurs. The calipers are removed and we are just talking about the interaction between the rotor assembly (e-brake portion) and the brake shoe assembly. Remember this is an adaption from 914 brakes to 911 types.

The shoes and the rotors were taken from an earlier 911. Any interference should have been negiable and everything should have bolted together. The rear bearings have been changed with the addition of Sway-A-Way axles, new CV Joints, etc. What the specific problem involves the ebrake shoes somehow not having and maintain clearance between the e-brake protion of the rotor and the brake shoe installation.

A lot of years ago I remember having a similar problem but cannot remember what caused it. I guess I will start cross referencing parts and taking measurements.

Sorry without picture I can't give you any advise. I had issues once when replacing the rear brake shoes on my 928s4, I couldn't get the rotor back on all the way. What had happened was the expander the cables hooked too, there was a piece that gotten turned around or put together wrong. Once that was found and put in proper order the rotor went right on. In short, it was holding the shoes out just a tad too far and it was hard to see with the eye, but just enough to not clear the rotor.
Pics help, post some. Good luck

Sounds like your backing plate is not 90 degrees to the axle. Look and see if it is hitting somewhere on the outer edge when you torque it down and bending it. If not, check to see if the actual backing plate is bent. Can't fix without pics.....

This happened when I assembled one of my trailing arms. The backing plate was somehow bent slightly and was rubbing the rotor. When torqued down it wouldn't move at all. A little persuasion from my channel locks and it was fine.

The idea that the backing plate could be bent or not installed properly to the swing axle after grindinng seems to be the most logical. I came to the samt conclusion the backing plate could be bent or not 90 degrees to the axle. I will check and see if it is true. I am thinking that the area requiring grounding of the ears was not completely ground down and I need to possibly address this issue.

I am also rechecking the stop welded in place inbetween the end of the two shoes.

Thanks for your input and assistance. Sorry about not providing pictures but I have been tied up inbetween the car and outside activities.

Give me a couple of days and I will get back to the thread with the cause of the problem and correction.

Thanks again,
Steve Hurt

The problem is the backplate and/or the grinding of the hub area to place the backplate on as tight and correct as possible. How do I know this?

The hub when placed on the studs and torqued down does not turn; spacing the hub and then torquing the lugs allows the axle to turn. Remember all the movement and stopage I had was attributed to lateral plane (direction: in and out on axle plane). It does move freely with approiate shims (washers used).

Most appropriate action is to see if I can remove the bolts holding the flange plate (holds bearings in) without removing the stub shaft. By going this route I can see if I need to remove the wheel hub (going to cost me a new bearing) and what are the possibilities of grinding the hub down for better seating. May also have to straighten the backplate. Depending on the outcome, I can proceed to correct the problem.

If I have to remove the hub (costing me a bearing) and I cannot get the retainer plate bolts out, then I will go to the temporary fix of shimming the rotor and the calipers. This should be functional and should last until I get the car ready and tested for the road. Still have to work details out.

The correct way is to grind down the hub flanges and fix the backplate on properly making sure it is perpendicular to the axle (90degrees); the backplate has to be checked for bending, etc.

The correct procedure if the bolts to the flange plate cannot be removed and hub ground down is to remove the hub thus costing a bearing and time to replace. Grind down the bearing hub flanges and make sure there backplate mounts correctly, is not bent, and 90degrees to the axle plane. Then reinstall everything.

The problem was caused by grinding down the hub flanges as per directions. I did not allow for the thinkness of the paint, etc. so I was marginal on everything which caused one side to cut into the rotor (e-brake area) when everything was assembled and torqued down.

Steve

final comments: The problem related to the seating of the backplates which was corrected by pulling everything apart and grinding the hub housing down thus allowing for the paint thinkness. By doing this, I also found a close clearance problem on the caliper mounting points with the rear of the rotor. Had to grind further clearance on the mounts so I had proper clearance with the inside rotor surface.

Everything is now reassembled and operating perfectly. I do not have any clearance, scrapping, or mounting problems. Now just service and bleed the brakes and take the car to the exhaust people for completion.

Then start sorting out the car mechanically and changing some minor items. Painting will go next year and thus we will be planning on attending the Porsche meet in 2014 (one in the Bay Area) with a complete and respectible car.