Diagnosinv Vac pump issues. - PeachParts Mercedes-Benz Forum

winmutt · #1 07-02-2007, 11:56 AM

I dont have any real amount of vac until the engine is revved. Do I need the rebuild kit or check valves? When it does build it goes in steps. 10 20 40 or so. This is mostly noticeable when braking with the engine in N. Goes completely hard the longer it coasts. I have replaced everything from the pump back without a solution.

tangofox007 · #2 07-02-2007, 12:13 PM

Quote:

Originally Posted by winmutt

I have replaced everything from the pump back without a solution.

Including the booster?

winmutt · #3 07-02-2007, 12:22 PM

Quote:

Originally Posted by tangofox007

Including the booster?

Yuppers. I think the pump rings just need to be replaced? It will hold vac just fine at idle, it just doesnt build any vac.

rrgrassi · #4 07-02-2007, 12:23 PM

How is the vacuum keeper on the locking system?

JimmyL · #5 07-02-2007, 12:35 PM

Which member of the fleet?

winmutt · #6 07-02-2007, 12:42 PM

Quote:

Originally Posted by rrgrassi

How is the vacuum keeper on the locking system?

AFAIK fine. Its one of the few things that functions well on the car. I am pretty sure the vac holds overnight. Certainly for a few hours. I have bypassed all of the clima as it is broken. I measured the vac at the vac pump from

[edit]
this is the 85.

Biodiesel300TD · #7 07-02-2007, 12:48 PM

Have you plugge your mity vac into the main vac line and then pull the line off the break booster and plug it, then start up the engine and read the vac? To make sure it's actually the pump. If so I would try a rebuild kit. Then a check valve.

winmutt · #8 07-02-2007, 01:02 PM

Quote:

Originally Posted by Biodiesel300TD

Have you plugge your mity vac into the main vac line and then pull the line off the break booster and plug it, then start up the engine and read the vac? To make sure it's actually the pump. If so I would try a rebuild kit. Then a check valve.

Ya that is what I am thinking.... I think the check valves are fine because once it build vac it holds.

Tnx for the replies everyone.

tangofox007 · #9 07-02-2007, 02:09 PM

Quote:

Originally Posted by winmutt

I think the check valves are fine because once it build vac it holds.

That tells you that the check valve in the nipple is okay. It says nothing about the internal check valves. But an overhaul kit includes the internal valves as well as the piston seal parts. Just don't be too quick to throw away your original check valve seals; the ones that are supplied in some o/h kits are too thin.

winmutt · #10 07-02-2007, 03:59 PM

Quote:

Originally Posted by tangofox007

That tells you that the check valve in the nipple is okay. It says nothing about the internal check valves. But an overhaul kit includes the internal valves as well as the piston seal parts. Just don't be too quick to throw away your original check valve seals; the ones that are supplied in some o/h kits are too thin.

Will do. I have a bad tendency not to throw away any car part.... The one thing about this is that the vac pump LOOKS to be fairly new...

kerry · #11 07-02-2007, 04:16 PM

The old style pump can be rebuilt in about an hour. No need to remove anything but shroud, fan and the front of the pump to replace the diaphragm and check valves. I think you probably have the old style on your 1980 if that is the vehicle in question.

winmutt · #12 07-02-2007, 06:17 PM

Quote:

Originally Posted by kerry edwards

The old style pump can be rebuilt in about an hour. No need to remove anything but shroud, fan and the front of the pump to replace the diaphragm and check valves. I think you probably have the old style on your 1980 if that is the vehicle in question.

Its the 85 as listed above...