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I bought a 1980 928 a few weeks ago, one family owned car from California originally and spent its last nine years in a garage in Ga. Only driven around 500 miles in 9 years and none the last two years. Engine was not running and had 129k miles on it. pretty much a mint car interior and paint wise. no cracks in dash or tears in seats. Had original full tool kit, clock worked. Daughter had thrown away original Blaupaukt. engine had not been modified and seemed to have had some reasonable mechanics working on it. a few electrical gremlins and vacuum hose fixes got the engine running, and running smoothly.
brakes were bled and the right rear brake was not releasing. changed all the flexible brake lines to steel braided and after a few miles none of the brakes would release . that finally resolved itself but now have a hard pedal and no apparent power assist to braking. takes around 60 lbs foot of pressure to bring the little girl to a stop. rotors and pads have been heat treated with the failure to release and am trying to find a source for front rotors. summit, speedway, pelican, parts geek, and chain auto parts places. all have rear rotors but not front rotors, only source was porsche Atlanta for 271 a piece front. any sources out there.
Have some electric problems, (imagine that) no power windows, no heater/ AC blower, wipers. Alternator is out. have cleaned all grounds and waiting on relays. painful part of the 928 is waiting on parts. Transmission has a rattle in 1st and was hard to shift until clutch linkage was adjusted. Now shifting is fine. found a .4 inch piece of metal on the transmission drain plug that we think is part of a tooth and from 1st gear. all other gears feel fine. and 1st is okay except for the rattle. Going to be sorting out the brakes the latter part of this week. Believe I have some trash in Master cylinder or proportional valve or a bad booster. Been driving the girl daily and trickle charging the battery at night. Great driving car. I have had a 71, 74, 80, and 83 911 and last one was sold in 1987. Great to be driving a Porsche again and love the car, even working on it at 76 years of age. Hope they have car lifts in the nursing home. My other car for school zones is a cobra replica 500 hp 351 cleveland.
You should replace the booster, rebuild the calipers (easy and inexpensive to do yourself), and send the master cylinder out to Whitepost to be rebuilt and sleeved https://whitepost.com/brake-sleeving...ding-services/
The proportioning valves rarely go bad, but if the entire system is corroded you should replace them. You'll have to remove them anyway to get the booster and master out.
Oddly enough, once you get the alternator in and working, you should replace the main ground strap on the battery, doing that usually fixes most of your non working items. It's probably corroded under the plastic sleeving.
Oh yeah, currently the only source for front rotors is Porsche.
It might be worth it to install the later S front spindles and calipers for the easier to get rotors. They also are way more effective at stopping the car than the originals could ever hope to.
https://www.buybrakes.com/1980-porsc...d-brake-rotors, Look at this site they have a good selection. I have used them for my cars, I like the cross drilled. I am in LaGrange GA, need to bring that Cobra by! Is it a Factory Five?
Dan it is a Everett Morrison built by a race car builder in Alabama. very well done and a great engine. Builder had it up to 165 mph. It is a true death machine and I am so glad I did not get one until I was in my 70's. david
Replace those original rubber brake hoses with braided stainless while you're at it. The internal rubber swells narrowing the passageways and the fluid can't pass backwards when you get off the pedal pressure. This is why many barn finds have to be dragged out of the barns with the wheels locked up - lines constricted and it's like they're applying the brakes.
Blake, thanks Much. We changed all the fluids in the car and all looked good when we changed. the Brake fluid was dirty close to the calipers but cleared up quickly. brakes worked great for about forty miles after the fluid change and flexible brake line change. I am off Thur-Sun and will get back on it. I wonder if we don't have some trash still in the system. f we dont get it fixed will send the master and proportional valve to whitepost. who makes a caliper kit that fits. I have read that some kits sold for our cars do not fit. will check out the spindle switch. This is the best forum I have ever been a part of . †he knowledge and help on the forum is incredible. †he newbie threads are a Godsend for us new to the 928. I have the rear ground strap on order. It comes in with the alternator on Apr 7. Will post progress at the end of the week. all the best. david
I replaced the lines with braided hoses when we changed the fluids. the drivers rear was not releasing when we started and we figured, as you mentioned we had a collapsing flexible hose. thanks. david
Brakes coming on after driving and not releasing is almost always the brake booster....
I almost always replace the master when the booster is out, as they are generally the same age.
Also, if the car is a manual, when the booster is out is the time to do the clutch master as well. Before installing, take the old clutch master apart and compare the piston length to the new one. The internal piston will likely need to be shortened about 5-6mm and a couple coils of the spring removed in order to allow enough travel and fluid movement to fully disengage the friction discs. It's no fun to put it all back together and then realize this issue - ask me how I know.
Thanks for all the source replies for the front rotors. NONE have any in stock. Even Porsche
Atlanta does not have any in stock. They are ordering them from Germany for me two months. Brake update to follow. david
03-28-2022, 11:49 PM
source front disc rotors for 80 928
