Brake pressure and warning light problem
10-27-2005, 05:28 AM
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Brake pressure and warning light problem
My "problem" is that according to specs it should take six hits on the brake pedal before the brake pressure pump should wake up. Mine starts pumping after one or two hits on the pedal...
So the symptoms are that there is a pressure leak somewhere in the system. However, my car spent a week at the local OPC and it was thoroughly tested both manually and with factory special tools but no leaks were found.
The maximum pressure in the system is 165bar and minimum 140bar. The lowest figure during testing that was recorded was 141bar, so its in factory spec. During a 30min leak test, according to factory standards, gave a result of 149bar, the minimum accepted being 140bar.
During this process the pressure reservoir, the pressure switch and the relay have been changed into new ones. The pump itself was also tested and it was OK.
The OPC says that the pressure is OK, but they don't know what causes the pump to act the way it does... They are not that experienced with these antique Porsches so they tried asking advice from the factory, but the reply was that nobody can remember so far back as how the 964 should work
(apparently the engineers that were responsible for designing the 964 have already retired...)
Any ideas what could be the cause of this "problem" and is it really a problem?
I don't know if its related to the above, but lately the brake and 4-wheel drive warning light goes on as the car is started and won't shut down until the engine is turned off. If I start the car immediately again the light doesn't light up. This behavior is very erratic and I haven't been able to work out the cause. As the brake pressure system has been checked I assume this is probably a problem in the electronics department. I'll be taking the car to my OPC next Tuesday so if anyone has any pointers I would surely appreciate them
Regards,
Ilkka - a Newbie from Finland...
So the symptoms are that there is a pressure leak somewhere in the system. However, my car spent a week at the local OPC and it was thoroughly tested both manually and with factory special tools but no leaks were found.
The maximum pressure in the system is 165bar and minimum 140bar. The lowest figure during testing that was recorded was 141bar, so its in factory spec. During a 30min leak test, according to factory standards, gave a result of 149bar, the minimum accepted being 140bar.
During this process the pressure reservoir, the pressure switch and the relay have been changed into new ones. The pump itself was also tested and it was OK.
The OPC says that the pressure is OK, but they don't know what causes the pump to act the way it does... They are not that experienced with these antique Porsches so they tried asking advice from the factory, but the reply was that nobody can remember so far back as how the 964 should work
(apparently the engineers that were responsible for designing the 964 have already retired...)Any ideas what could be the cause of this "problem" and is it really a problem?
I don't know if its related to the above, but lately the brake and 4-wheel drive warning light goes on as the car is started and won't shut down until the engine is turned off. If I start the car immediately again the light doesn't light up. This behavior is very erratic and I haven't been able to work out the cause. As the brake pressure system has been checked I assume this is probably a problem in the electronics department. I'll be taking the car to my OPC next Tuesday so if anyone has any pointers I would surely appreciate them
Regards,
Ilkka - a Newbie from Finland...
10-27-2005, 06:39 PM
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Nordschleife Master
Hiya Ilkka
The fluid / pressure from the pressure reservoir (the bomb) is going somewhere , the fluid must cycle back to the brake fluid reservoir . Find the hose that is sending lots of fluid back to the brake fluid reservoir , trace that line back to the "leaker" ? Might be a big mess , but thats the way I think I would try and track it down .
How freaking cold is it in Finland ?
Any photos of you and your car ?
The fluid / pressure from the pressure reservoir (the bomb) is going somewhere , the fluid must cycle back to the brake fluid reservoir . Find the hose that is sending lots of fluid back to the brake fluid reservoir , trace that line back to the "leaker" ? Might be a big mess , but thats the way I think I would try and track it down .
How freaking cold is it in Finland ?
Any photos of you and your car ?
10-28-2005, 06:31 AM
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Thanks for the pointers Indycam!
We've had the first freezes and snow falls over here, but nothing harsh yet
The C4 becomes handy when the roads become icy and snowy
A few, not so good, pictures can be found here:
http://public.fotki.com/Audifin/
They are from my first trip to have a look at the car. I haven't had time to take any proper pictures yet. The Cup-1's have been replaced by Cup-2's for summer tyres and 16" Cup-1's for winter tyres.
We've had the first freezes and snow falls over here, but nothing harsh yet
The C4 becomes handy when the roads become icy and snowy
A few, not so good, pictures can be found here:
http://public.fotki.com/Audifin/
They are from my first trip to have a look at the car. I haven't had time to take any proper pictures yet. The Cup-1's have been replaced by Cup-2's for summer tyres and 16" Cup-1's for winter tyres.
