I'm hoping I can get some advice on replacing the hydraulic pump in my C4.

Well as luck would have it, I lost my brakes about a block from the house this morning, and made it down to the garage using the parking brake. Shortly after droppng my daughter off at school this morning, I heard a low motor hum from the front of the car, decided to head home, and shortly after had the Brake and PDAS and warning beeper go off.

Fluids look good, no leaks, and the #15 fuse is ok. The hydraulic pump has a burned smell, and I suspect that is the source of the problem.

Any suggestions on testing the pump? and if it is the pump, any suggestions on where to get a replacement? It does not appear to be the typical stocked part... but I did see one for a 993 at: http://cgi.ebay.com/ebaymotors/Porsc...ayphotohosting ouch!


Thanks in advance!

Tom

 

I sent you an email .

 

There's a new one on eBay.....

http://cgi.ebay.com/ebaymotors/ws/eB...1784&rd=1&rd=1

 

Oops.....nevermind, that's a master cylinder. Sorry!

 

Porsche dealers can get them - call Sunset and they can order one as I looked into this about 8 months ago.

 

had the same problem 2 yrs ago---only mine was leaking profusely. i have a 90 c4. tried replacing o rings to no evail. called a porsche dealership and got a quote for around 1800 dollars--decided to look elsewhere and finally found one at german auto dismantlers. paid around 450 bucks USED. i have seen some on ebay that were supposedly for a 964 that looked nothing like mine; and am not sure if this pump is different on the c4. anyway-- this was such a PIA that i am always looking to pick up a spare. i was talking to a guy in michigan who is dismantling a couple 964s today to find a part i need and mentioned this to him. he has one from a 91 c2--check your part number, and you might want to give him a call. Rick at 517-321 2774. hope this helps. tom

 

Did you get my email ?

 

I don't recommend it, but I drove for about 7 months without mine. The brakes WILL work, but you better have strong legs. Luckily, my problem was the pressure switch, not a burnt out pump motor - so Sunset solved my problem with a good price on a new switch.

 

Thanks Guys!

Its amazing...but it sure does not look like too complicated of a part...but then again, I've not yanked one part like our good friend "Indycam".

I'm in New Orleans for a long weekend for Mardi Gras....I'll give you an update next week.

Again, Thanks!

 

"Sunset solved my problem with a good price on a new switch."
Do you recall how much $.
It would be a bugger to replace the switch and find it was not the switch .

 

Don't remember the exact amount, but in the region of $150. Certainly under $200 anyway.

 

Don't forget that when you replace it, you will need to bleed the system with the Bosch Hammer or Porsche PST2.

 

I've switched in between pumps a few times ,I have three good working ones now , and have never needed the hammer .
The pump blows into the bomb , the bomb has a bleed nipple , hook it all up , open the nipple , try to prime the pump , when the pumps primed , run the pump the run fluid into and out of the bomb ...

If I'm missing something ...

 

Don't C4's need the hammer to open and close the diff actuators? If not, how do you do it without a hammer (be nice to know how-to, making the biennial fluid flush a DIY activity)?

Or are you assuming that the lines past the bomb stay air-free?

 

How would air get down stream from the bomb ?

If you remove the hose to the bomb from the pump end , the fluid stays in the line , the fluid stays in the bomb . When the pump is removed the hose to the bomb stays filled with fluid . So how would air run down the fluid into the bomb and then past the bomb ?