MF 135 Thrust Washer Replacement

Hello,

I have a 1967 MF 135 with the AG3.152 Perkins Diesel engine. I have been experiencing loss of oil pressure on the tractor. Fires up great, and starts @ around 60 and slowly drops down to 10 over the course of operating. Based on advice I found here and elsewhere I decided to try replacing the oil pump (thinking the overpressure spring was stuck open, or oil pump otherwise shot). This is a good place to say: I am a newbie to working on older tractors but have a decent mechanical know-how.

Got the oil pan dropped just fine and was surprised to find an upper and lower thrust washer living in the bottom of the oil pan (yay! - not). I am proceeding with oil pump replacement since I already have the parts and pan off, but now I am wondering about replacing the thrust washer (and if maybe oil seepage here was causing loss of pressure - although tractor leaves a very minor oil spot its not much).

Is it possible to remove the rear main bearing cap to replace the thrust washer without splitting? It appears visually and in diagrams to be secured to the rear main oil seal plate by 3 screws that I cant access very well currently. Also, I think I can see the spot in the rear main bearing cap where the thrust washer sits, but I am assuming I need to get the cap off to get it seated in there properly (? like I said - newbie).

Hate to split the tractor just to replace a $3 part as the main bearings have already been renewed shortly before I bought the tractor (Although I am now questioning how good of a job they did given that this thrust washer obviously wasn't secured properly, or blew out due to crank walk). Any thoughts or creative tips on how I can get over this hurdle?

Thanks to everyone that posts here, this has been an amazing resource to help me learn!

- Andrew

Sorry, AD3.152, not AG, mistyped

Hello Andrew,
If one pair of washers has dropped out then it is likely that the ones on the other side of the main bearing cap may have done so as well. Are the washers badly worn. If only one pair has come out can you identify from which side? If they are from the rear side and the tractor has been used for any length of time then damage may have occurred each time the clutch pedal was pushed down as the crank was forced against the journal and main bearing cap. This would not affect oil pressure. To replace the thrust washers it will be necessary to split the tractor and remove the clutch, flywheel and backplate. The oil seal retainer will need to be removed too before the cap can be removed. Inspect for damage. Fit a new set of thrust washers and measure the crank endfloat with feeler gauges. It should be between 002 and 015". If it is outside this figure oversize thrust washers are available in +0.075" oversize. When replacing the rear crank oil seal I would suggest that you only fit a genuine Perkins one. Non-genuine ones look the same but the material is harder and will pass oil once the seal starts to wear. The genuine ones can compress and keep a good seal. It will cost more but its well worth it. Let us know how you get on.

DavidP, South Wales

Thanks David!

Whew, looks like a might get a chance to do the clutch too, fun! Perhaps I can replace/repair the tachometer while I am at it, as it is currently non-functional.

Above is a pic of what the thrust washers looked like after I retrieved them from the pan and cleaned them up. I wouldn't be surprised if there was damage given how the upper one looks. I will check the parts diagram when I am back in the shop this evening, but I believe the pair that came out is the front pair, not rear (although maybe this is just wishful thinking). This is only based on trying to peer around the edge of the bearing cap on the front side and seeing a spot where it looks like the tab on the thrust washer would seat, and there not being any washer in there. Not the best way to diagnose, I know, but all I have at the moment.

If I am going to have to split, would it, in your opinion, be wise to check tolerances on the main bearings to make sure they aren't worn or damaged since I will already have her apart? Or anything else I should keep an eye out for?

I hear you on the oil seal, as I have seen that comment in other places as well. It looks like whoever did the seal before just used an a$$load of gasket cement to make sure it didnt leak, as I can see places where it dripped out, lol.

I am assuming running the engine with only one set of thrust washers would be paramount to trashing the camshaft/block? I clearly should have started this project before it was almost time to till the field, haha.

Thanks again for your help!!!

Hi All,

Just a little update on progress here. First off - thanks to DaivdP for the pointers. I got the tractor split and I'm sure glad I did. It was indeed the front thrust washer that had come out, I found the two pieces of the rear thrust washer jammed over eachother in an overlapping position above the crankshaft (the retaining tab on the lower one has sheared off and it rotated up into the top position. Crankshaft looks okay to me, no obvious gouges (see pic). However, main bearings arent looking great (pic) so I am going to go ahead and do those while I am in there. Overall it has been a great learning experience - thanks to everyone on these forums! I have gone through every post I can find on putting things back together, but I am always open to more advice =)

This is my list of things to take care of before I put things back together - let me know if any of you have an idea on an important maintenance item I may have missed:
- Main bearings
- Thrust Washers
- Oil Pump
- Rear Oil Seal & all other seals I took apart
- Clutch (in pretty bad shape - so I figure why not, save me another split)
- Ring gear
- Flywheel pilot bearing
- Transmission Seal leak (pic)
- Also there is some play in the PTO shaft, not sure if that is an issue I need to deal with right now - open to input!!! (pic)

Also a couple other minor things to take care of:
- Fuel sending unit
- Tach cable (was rounded off @ the end)
- Tie rod boots


Thanks again everyone, I will update again when I get it all back together and running!

The crankshaft doesn't look too good, wore it pretty good where the thrust bearing runs. Looks like another crankshaft is in your future. While it could maybe be re-ground at the thrust surface, and use thicker thrust washers (the thrust surface on the crank will be looking rather thin). The thrust surface is one place I don't like re-grinding a crankshaft unless there is no other way to increase the clearance if needed.

Thanks for the feedback ptfarmer! Not what I was hoping for, but better to know now than later! I will try to get some better pictures tonight if you wouldn't mind taking
a second look.

Also, after looking at my manual it seems like new connecting rod bearings should be part of the rehab as well. Thoughts?

My shopping cart is getting larger and larger... =P

The main bearing in the cap doesn't look bad, no copper color showing. Look at the block, and main cap where the thrust bearings were, and make sure it doesn't kind of look like that main journal. Sometimes it can wear the block like it did the crank. You maybe better off $$ wise getting a short block rebuild kit, or another short block that's been rebuilt rather than piecing together just the individual parts you may need, shop around!