Repair Stihl Chainsaw Oil Pump (1 Viewer)

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Hello,
This is a wonderful thread on the Stihl 028 line, with a mod (including D'Animal, and others!)who actually
has great knowledge and insights on these and other models . :)
I have been reading but only today joined to be able to ask my own question, and hopefully others
can benefit from it here.
I have a couple of 028's (bought one new in '81!) and on one, the AV WB with brake, I have a messy
black oil being thrown around inside the brake/oil pump cover. It then seeps out the bottom as well,
coming around the clutch drive gear cover (round metal plate around the pto shaft hole). It's not nice
clean chain oil! It's really black and messy. I am attaching a pic of the cover and where the oil appears
to be escaping (?).

The pump gear doesn't want to pull out more than about 1/4", with turning and pulling moderately,
not forcing it. It turns very easily, also the oil is delivering to the chain bar ok.
It's just the mess I want to fix!
I can't pull anything further to see behind it all with the pump gear not pulling out to get to the screws.

Now, there is BLACK oil coming out from the tiny center hole in the pump gear shaft (see pic with the
oil streak coming down the side of gear). You can pull the gear out a bit and push it in a bit, and the oil
seems to be coming from the little 'pumping' back and forth like that, however, it also comes out when you
run the saw with clutch turning, just seeps out a little at a time, but obviously ads up a lot to make the
mess!
stihl 028 oily cover.JPG




stihl 028 oil pump leak.JPG

I did a major choke cleaner and air cleanout of the housing behind and around the clutch, brake and oil
pump area!

I don't think this is normal! My other 028 has no brake, and also stays dry in that area.
Can you give me some thoughts on the above issues, and what I can do to make it right?

I hope this posting displays properly! We shall see :)

Thanks for your time and advice!
Dusty
 
The oiler gear that goes into pump can be removed. You "unscrew" it like you have done before. Once unscrewed, reach under the gear and grab the center shaft with a pair of needle nose pliers and pry/pop it off.

You can then access the screws and remove the oil pump.

You can disassemble the pump and check it for wear.
 
The oiler gear that goes into pump can be removed. You "unscrew" it like you have done before. Once unscrewed, reach under the gear and grab the center shaft with a pair of needle nose pliers and pry/pop it off.

You can then access the screws and remove the oil pump.

You can disassemble the pump and check it for wear.

Thanks for the advice!
Before I do that, *note* that I don't have to 'unscrew' the wheel to move it out 1/4" or so, it just pulls out and pushes straight in, like it's loose, but then won't pull any further. Does the wheel come loose from the shaft without damage? Looks like there's a spline under there.. ?
What is in there that could be holding the shaft in, is it a circlip, a seal, or? Are seals available to replace these parts? Have searched online and not seeing a pump 'refresh' kit, with hoses etc.. just an oil pump pickup hose.

Maybe the pump is rotating out of the worm gear, instead of making me unscrew to pull out? But it stops there, and I'm reluctant to force it out, since the pump works fine so far. Just has this leak coming from the hole in the very center of the shaft (hole is about the size of a thin paper clip).


Is that oil seeping from the pump gear in the pic, indicative of something you are familiar with?

Thank you
Dusty
 
I'm back from my road trip.

I don't know your location so I cannot recommend a local place for you.

The oiler is super easy to replace. I doubt it is the pump. It is probably the oiler drive gear. Is the saw all tore apart?

Here is how to check it out yourself.
Take your bar and chain off.
Remove the metal plate that is around the bar studs. One screw in the middle between the studs holds it on.

Remove the clip on the end of the crankshaft. Once that is removed depending on the version of 028 you will have another washer and a large clip holding the washer onto the cranshaft. The 028 Super should have a rim sprocket but it will still ahve two clips and two metal washers.

Remove the large plastic cover that is about the size of you hand and kinda looks like the state of Michigan. Once that cover is removed you will see the oiler drive gear sitting on the sprocket drum. The oiler driven gear goes into the pump and just pulls off. The gears are plastic and are designed to wear. They are the weak link in the system.

This is about a 10 -12 minute repair, not counting cleaning time.

I doubt you need a pump unless you have been running used motor oil as bar and chain lube. I have probably replaced 500 oiler drive gears and two pumps in the last 20 years.

Let me know if you need any pictures and any other questions answered.

Dan

Ha. Google brought me to MUD as usual as I'm trying to repair my 028 Super.

Thanks, dude.
 
Old thread, new guy, loved the previous info, so, here I am!

Stihl 028 WB. My Dad bought it new in 1985, and gave it to me when he upgraded. I love this saw and it has treated me well. Unfortunately, the chain started to get hot, and I eventually wrecked the Oilomatic E bar. Also noticed oil leaking out of the bottom. I'm pretty tech savvy, but I have a newborn and other responsibilities and didn't want to tear into it because I didn't have the time. Brought it to a shop that wanted to charge me 300 dollars because the oil pump is leaking and starving the bar, and it needs to be replaced.

I said, "thank you, but I'll take it back in pieces."

I took a look at it, and the pump does push oil out, but I believe they ripped the seal out of the pump. I can buy a new pump from them for 90 bucks, but thought if I could get a new seal, and ask you great people some questions, maybe that would be better. Gears all look good, so please have a look at the following pictures and give me some input if you can. Thank you in advance!
1919658
1919659
1919660
1919661
1919662
 
Old thread, new guy, loved the previous info, so, here I am!

Stihl 028 WB. My Dad bought it new in 1985, and gave it to me when he upgraded. I love this saw and it has treated me well. Unfortunately, the chain started to get hot, and I eventually wrecked the Oilomatic E bar. Also noticed oil leaking out of the bottom. I'm pretty tech savvy, but I have a newborn and other responsibilities and didn't want to tear into it because I didn't have the time. Brought it to a shop that wanted to charge me 300 dollars because the oil pump is leaking and starving the bar, and it needs to be replaced.

I said, "thank you, but I'll take it back in pieces."

I took a look at it, and the pump does push oil out, but I believe they ripped the seal out of the pump. I can buy a new pump from them for 90 bucks, but thought if I could get a new seal, and ask you great people some questions, maybe that would be better. Gears all look good, so please have a look at the following pictures and give me some input if you can. Thank you in advance!View attachment 1919658View attachment 1919659View attachment 1919660View attachment 1919661View attachment 1919662

Aaaand 2 more pictures

20190304_181537.jpg


20190304_181557.jpg
 
@D'Animal
Any thoughts? You seem to know a lot about these.
The worm gear pulls out with no resistance. Looking at where it sits, it seems like there should be a seal there since the opening has a shoulder. Either way, I guess this whole thing depends on whether or not I can get parts.
 
Well, at this point, I'm talking to myself. But maybe this will help someone in the future? Talked to a Stihl dealer that can get me a new seal for the top, and a new gasket. Parts aren't bad when you're talking individual pieces instead of the whole thing. The pin rides in a groove of the piston pump which is what pushes the oil. Nice tight tolerance still. Piston fits tight too. Going to order the seal and gasket and see how it goes!

20190305_184740.jpg


20190305_185120.jpg


20190305_184745.jpg


20190305_184800.jpg
 
Well, turns out the older 028 pumps with the fully plastic gear don't require a gasket. Amazing how difficult it is to find info on this. Going to say screw it and replace the gasket for the mating surface of the pump to saw only, and see what happens.
 
Well, replaced the gasket between the pump and the saw. When I said "dont require a gasket" in my previous post I meant a seal to seal the drive gear. Anyway .... Found a decent way to test the pump without running the saw. Stuck some automotive seal to the end of an extension and chucked it in my drill. Looks good. Been a day or so and the gasket seals great. Nothing like a homemade gasket to keep it cheap! Hoping my leak stays away. Picture below is me spinning the pump with my drill. More to come...

Screenshot_20190314-204151_Video Player.jpg
 

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