stihl 032 av oil pump rebuild

[sven556]

I have a stihl 032 av that leaks oil behind the cover that is behind the sprocket. I hope that makes sense. It has to be coming from the pump itself; either the gasket between the pump and crankcase, or the seals on the pump itself. Looking at the IPL there are two o-rings, the rubber plug at the end of the oil pump (part no. 0000 988 6220), a sealing ring (part no. 9643 950 1160), and a "rubber ring" (part no. 0000 989 0401) that seal the pump itself. Does the "rubber ring" actually seal anything? It looks like it just covers the spring and doesn't keep any oil from leaking.

I've inspected the crankcase and don't see any cracks. I would like to rebuild the oil pump but I'm not sure how to disassemble it. I can't get the control bolt to compress where I can remove the pin. Any suggestions?

 

[HarleyT]

Just by a used one off of e-bay..

http://www.ebay.com/itm/Stihl-030-0...329832?hash=item4b0a5bb668:g:IpMAAOSwxKtX~4rJ

 

[hotshot]

That end plug is there just to keep out dirt.

To get the pin out, turn the control bolt "adjuster" fully CW, then push on the adjuster to make the pin rise just high enough over the cam track to remove & it only drifts one way as its a taper pin.

Needle nose vice grips work well, & it doesnt take much as that spring is almost solid heigth. Mark the adjuster or take a pic before you pull it out, as it can be installed 180 out. The "small moon" is towards the plug end when adjuster is CW, see pic.

The two midget sized orings are likely bad, but the driven gear shaft seal could also be leaking given the saw's age. Some of the later pumps had no shaft seal, so take Harlets advice if thats the case and buy one that does.

You can cobble up an inlet pressure test to check, the bottom slot is the inlet, so blind the top slot for a quick pressure test with soap bubbles or Windex

 

[sven556]

Thanks for the picture Hotshot. It was about a 5 min job to replace the o-rings after I saw your post. Now I need to get a new shaft seal and it should be good as new.

 

[hotshot]

Good deal & good on Stihl for providing the oring sizes.

Did you notice the two different eccentrics cams on the control bolt?

If you push the bolt in hard at the "-" position, then rotate 90 degrees CCW to "O", it totally shuts off the pump for running the powerhead for testing w/o the bar & chain

 

[sven556]

Yes, I dd notice the eccentrics. I think I read about shutting off the pump in the service manual. I had to buy something like 7 o-rings of each size from an online store but they were cheap and didn't add up to much.