Problem with my breakes, need help

[Jesper]

Hello Friends

Recently I bought this awesome 930 from CA. The car has not been driven a lot in the past couple of years. I take the car to a break stand to find out if the car breaks right. After the break test, I have some problems with the breaks. You have to excuse me, for my bad English technician writhing, and I hop you can understand my question. The break pads will not let go the discs, as they should. I can drive the car, but when I turn, the pads will touch the discs. I am aware of that the pistons in the calipers wont get back as it should. My question; is it possible to remove the pads, and give the pistons in the calibers some massage? Alternatively, do I have to buy a rep kit with new sealing? It’s very important to have in mind, that the calibers, discs and the pads is brand new, its just be course the storage. The calibers and discs are not the original 1976 breaks, but upgraded to Porsche Boxter breaks by S-CAR- GO RACING in San Rafael.

Thanks for a great forum.

Best regards
Jesper, Denmark

[HelmetHead]

Jesper,
Sounds like the calipers are sticking. Start by rebuilding the caliper pistons and then if that fails, you might have bad flexible brake lines?

Good luck,
Einar

[550SPYDER]

Jesper - if the pads do not rub until you turn, you have an issue with the hydraulic system that is causing brake fluid to apply pressure to the system when the wheels are turned. The best case would be that it is being caused by a crimp in the line that appears when the lines are expanded on one side by turning or contracted in the other. To test this jack up the front of the car and turn the wheel to one lock and check the brake lines then repeat on the opposite lock and check the lines again - your wheels should be able to turn freely lock right, center and lock left.

[Miguel Antonett]

If the car has been sitting for a while, I would drive the car and exercise the system allowing the pads to properly self-adjust; however need to be carefull and aware of the situation not to damage something else. Assuming flushing/bleeding and checking of the brake lines has been done already.

[full quack]

My car sat for about 3 years before I bought it, and after a very short period of driving, I too had calipers that were "hanging up". Mine caused the car to inconsistently pull from one side or another, whether on the brakes or not, worse of course when the brakes were applied. Maybe you have a similar situation.
Anyway, rebuilding the calipers solved the problem completely. Hope yours is as simple to remedy!
Mark

[Craig 930 RS]

1) Flush master cylinder and lines, and of course calipers. Complete flush.
2) Jack up car and manually test and exercise the pistons after removing the brake pads
3) Using information from that, perhaps take it on the road for a road test/reality check
4) Possible caliper rebuild, but maybe not.

A sitting car = an early death to components.

[fredmeister]

Before you rebuild the brakes......replace the bake fluid for sure.
Then you may consider replacing the lines if they are original and look to be non-damaged.
Your call.
You can massage the pistons....I was gonna say something stupid about the Swedish people being good at that....but I wont.
Seriously, remove the pads from one side of the caliper leaving the other in. Insert a thin piece of wood to prevent the pistons from completely blowing out of the caliper while you have someone press on the brake pedal to move them towards the rotor. Push them back in and cycle this way a few times. Then do the other side of the rotor.
They should go back in under uniform pressure fairly easily and you will be able to find if any of them are hanging up.
Sometimes they need a little cycling thru their range of travel to loosen back up. I would try this before rebuilding them which is a big job.

[Craig 930 RS]

Exactly, well put Fred.

[Turboo934]

Ive seen person's spend thousands on rebuilding their brakes and leave the old flex lines. Also flex lines need a preset twist when installed so they don't kink under suspension movement or steering.

[A930Rocket]

I'm wondering why the "upgrade" to Boxter brakes? IMHO, it's not really a good upgrade. I don't think the rotors have enough heat sink capability and wonder about pad/piston sizes.

[Craig 930 RS]

Ah, I missed the Boxster brakes. A downgrade from OEM 930 brakes for sure.

[Turboo934]

You also missed it's a 1976 turbo.

[Craig 930 RS]

Sure did! That's what you get when I read the post way too fast.
I'll bet the brakes aren't too hard to fix - modern piston and seal material will sure help.

Let us know how she works out!

[Jesper]

Hi Guys

Thank you all so much for your comments. It means so much to me, to get the right help from you people. I will use this forum a lot, and I appreciate your help, but please bear over with my sometimes ignorant questions. In the nearest future, I will try to fix the breaking problem by go through your “to do list”. I am very sorry to hear, that the “upgrade” to Boxter breaks is for the worse. Seller told me they were breaking a lot better, and it certainly was an upgrade? Should I try to locate the original 930 calipers, and mount them instead? I have attached a few pictures of the breaks. One more question this time. The last pictures show a cylindrical container with a little yellow ball, is this for the A/C or what? What does the yellow ball indicate, pressure?

Again thank you very much, that’s all for now.



Best regards
Jesper, Denmark

[A930Rocket]

The yellow ball is in the receiver/drier portion of the AC. When the AC is on the yellow ball floats around as Freon flows. If it's not moving, your AC isn't working.

What are the dimension of the Boxster rotors? I want to say stock 930 rotors are 32x332?

[Turboo934]

Jesper : 76 Turbo's are unboosted braked cars . Check and see if master cylinder has been upgraded to a 23 mm .

[WERK I]

Originally Posted by Jesper

Hi Guys

Thank you all so much for your comments. It means so much to me, to get the right help from you people. I will use this forum a lot, and I appreciate your help, but please bear over with my sometimes ignorant questions. In the nearest future, I will try to fix the breaking problem by go through your “to do list”. I am very sorry to hear, that the “upgrade” to Boxter breaks is for the worse. Seller told me they were breaking a lot better, and it certainly was an upgrade? Should I try to locate the original 930 calipers, and mount them instead? I have attached a few pictures of the breaks. One more question this time. The last pictures show a cylindrical container with a little yellow ball, is this for the A/C or what? What does the yellow ball indicate, pressure?

Again thank you very much, that’s all for now.



Best regards
Jesper, Denmark

Jesper,
Do you know if the master cylinder was upgraded when the rotors and calipers were upgraded? A photo may help.

Since these are aftermarket rotors, I wonder if it is a question of rotor thickness versus brake caliper. It looks like the pads are new.... Maybe the pads are fully retracted when you turn into a corner and can't retract any further? Also, have you checked to see if there is some looseness in the front wheel bearings?

Since the early 930's used 911S calipers/rotors, the Boxster "upgrade" would be better than the 911S's.

[Craig 930 RS]

Yes for certain those calipers are better than what came with the early, early 930 - by quite a bit.

[Flieger]

Boxster brakes are better than the 76,77 Turbo but not as good as the 78-> 930/917 calipers.

[beepbeep]

Slight squeal is OK, but if brakes are binding after application then something must be done. Lift the car, apply the brakes and let go. Then try to move the wheel by hand. It should turn fairly easy.

1. Change brake lines (I prefer OEM rubber ones). Braided lines are visually nice but you don't know the condition of rubber underneath. Old line can create "flaps" which act as one-way valves and let the fluid forward but not back. This will keep pads pressed against the rotor.

2. take out the pads, "exercize" the pistons slightly couple of times by pushing them in/out (make sure they don't get pushed out fully by misstake).

3. make sure pads aren't binding in the calipers. If they do, file the edges of pads slightly until the move freely.

4. Make sure MBC is healthy and pedal return spring works as it should.