1985 vac pump rebuild- pic.tutorial - PeachParts Mercedes-Benz Forum

minimike1 · #1 02-21-2008, 06:17 PM

Is there a picture tutorial for rebuilding a single line vac pump?
I've seen the thread for the other rebuild, but it does not apply.
This is a single line pump.

Can it be done in the car?

I've attached a pic of what my pump looks like with the cover removed.

Do rebuild kits come with detailed disassembly and installation instructions?
Mike

Stevo · #2 02-21-2008, 06:29 PM

Heres one that I used, theres one around with pis someplace also.

1) Loosen the power steering pump belt and remove it to get it out of the way.
2) Remove the top radiator hose.
3) Remove the metal vacuum hose from the pump.
4) Clean the gunk out of the Allen head bolts holding the pump to the engine.
5) Remove the six bolts and pull the pump off and out.
6) Clean the gunk off it
7) Remove the seven slotted screws that hold the pump housing together. Have a hammer and chisel ready. Save one for the impending trip to the hardware store. M5x16, .80 thread.
8) Note the orientation of the three valves. The replacements must go in the same way.
9) Loosen the nut in the center of the piston. Provide pressure on the arm on the back to help with this.
10) Push the piston out of the bore from the slots in the back using a Popsicle stick.
11) Remove the weird cardboard-like band from around the piston and the o-ring underneath it. Clean the piston up and smear some oil on the new o-ring and band before fitting them onto the piston.
12) Clean out the piston bore, and smear some clean oil in it. Carefully push the piston into the bore (you remembered to put that washer back in there first, right?) and struggle to get the spring loaded threaded rod back through the center of the piston. Replace the outer washer and new captive nut. This is the hard part.
13) Fit the new seals for the three valves, then drop in the valves in the original orientation.
14) Fit the new cover seal and put the cover on, using the new screws from the hardware store.
15) Loosen the fitting on the top where the vacuum line connects. Inspect the check valve in there and make sure it works. Replace if needed.
16) New gasket (or sealer, if you've forgotten to order a new gasket) and re-install the pump, vacuum line, power steering belt, radiator hose.

minimike1 · #3 02-21-2008, 07:35 PM

Stevo,
Excellent.
Why new screws on the face plate cover? I'm sure the Chinese screws I buy today are inferior to what MB originally used.
Also, What's the chance that my loss of vacuum could be only the check valve?
anyone have that picture link?
Mike

Stevo · #4 02-21-2008, 08:34 PM

Quote:

Originally Posted by minimike1

Stevo,
Excellent.
Why new screws on the face plate cover? I'm sure the Chinese screws I buy today are inferior to what MB originally used.
Also, What's the chance that my loss of vacuum could be only the check valve?
anyone have that picture link?
Mike

Yah, check the check. Not much room to get at it but its right on top where the line comes out. I have not done the check valve in the car but its sounds quite doable, allot easier than removing the pump only to find its the check valve.

blindwolf · #5 02-22-2008, 12:43 AM

hope this helps.

minimike1 · #6 02-22-2008, 09:11 AM

Blindwolf,
I can't open that file. Can you post a link for me. That would be easier.
BTW, I've gotten em's about other vac pump rebuilds. One says there are 3 check valves. I only see two at bottom of pump with the cover off as in my pic in the first post. Is there an exploded diagram of the late style vac pump in any of the books I can access or a link? I"m a picture kind of guy. No instructions needed, just pix. Duh.
Started as a kid, and can't break the habit.

blindwolf · #7 02-22-2008, 11:42 AM

The link that I used is no longer in service. The third check valve is where the vacuum line screws into the pump body.

tgingrich · #8 02-22-2008, 05:40 PM

Compare the thickness of the check valve rubber seals before you put the new ones in. My replacements were thinner so air leaked by and made no vacuum. I got to take it all apart again.

Stevo · #9 02-22-2008, 07:08 PM

Ouch, good tip, thanks

minimike1 · #10 02-23-2008, 09:12 AM

I think I"ve viewed every thread on vac pump on this board and some others going back to 2002. Still looking for an exploded view of the single hose late style vac pump. If someone has a single page they can fax but can't em, pm me and I'll give you my fax#.
BTW, when I do rebuild the pump, I'll take pix for a tutorial for others.
What I want to know is what is connected on the back side of the pump to drive it. I don't want to lose any bits inside the ip or engine side of the pump that pop apart when I remove the pump.
Thanks.

Stevo · #11 02-24-2008, 06:32 PM

Be careful there are a couple allens, when removing the vacuum pump, that are a little tricky too get the wrench into straight, easy too strip out. I use a single allen on those, not my 3/8 drive one.

minimike1 · #12 02-24-2008, 08:04 PM

I'm thinking that I might swing the rad to the side to access the pump from the front. I've got a pm from Dave who is going to fax me a tutorial on the pump r & r. Today it warmed up a bit and I swung the ps pump to the right, and removed the fan. Also degreased the pump housing with diesel fuel and a brush. Wow was this thing caked with crud. Stevo, in your instructions you posted, there is nothing about how the pump keys into the drive. Whats the story there?
Mike

tgingrich · #13 02-24-2008, 08:39 PM

From Stevo's post -
4) Clean the gunk out of the Allen head bolts holding the pump to the engine.
5) Remove the six bolts and pull the pump off and out.

Take it out of the car.
The pump has a roller bearing that rides on an eliptical ridge moving the piston up and down as the ridge on the timing chain driven internal wheel turns.
I mounted mine on a board as in the tutorial to compress the spring and take the thing apart. I don't have pics, but I'll look for the tutorial I used - it had them.

I found the diy I used, but the link is broken

Rebuilding the vacuum pump
Our vacuum pumps last quite well but one part failure in it may cost the whole part to quit working. Richard Easley made a very nice page full of good pictures on how to rebuild your old pump. Rebuild kits can be had for far less money than what it'd take for a new pump.

http://business.baylor.edu/Richard_Easley//autofaqs/Vacuum%20Pump/Rebuild_vac_pump.htm

Perhaps you could contact Dr. Easley
richard_easley@baylor.edu

Stevo · #14 02-24-2008, 09:17 PM

Quote:

Originally Posted by minimike1

there is nothing about how the pump keys into the drive. Whats the story there?
Mike

There is a bearing on an "arm' on the vp that rides on a little 'roller coaster" track on the "timing device", which works the piston of the pump. It will be quite clear then you pull the pump. Make sure the balls in "bearing are OK. Also pull the timing device in and out, there shouldn't be more than a mm of play. If you have a Haynes manual theres a good pic and explanation.

minimike1 · #15 02-24-2008, 10:10 PM

like Columbo, before I leave, one more question..... The main vac hose that goes to the booster is a clear plastic?. and the T and each end is pressed onto the tube. Is that oem tube still available? Or what would I use in it's place? There's the slight possiblity that the cause of low vac. is due to a leak where the vac pump side is connected to the T. Reason I know, I undid the tube at the top of the pump to have a look and the tube rotated quite freely at the T joint. When the mity vac arrives, I'll test that first, but I am assuming that I will need to refit the pump with new innerards.
Stevo, and TG, thanks very much for keeping up with my thread. I'll also try to contact
Richard Easley.
Mike.