Michigan 75A no forward travel

[Burnt.Fingers]

Found the new clutch discs at General Gear & Machine, Boise Idaho. at a good price. (steeringclutch.com)
Minnpar.com had the topcover gasket, O-rings, clutch hub sealing rings but only 2 of the 4 outer clutch piston seals and none of the 4 inner seals or any of the release springs.

I'm still searching for:
4- inner clutch piston seals - part# 208777
2- outer clutch piston seals - 208776
40- clutch release springs - 209709

Connected the brake line off the master cyl back onto the transmission top cover while I had the cover off and bled the brakes then checked the valve in the top cover for brake fluid leaking- the valve is holding pressure perfectly with no leaks anywhere, hydrovac and all 4 wheels no leaks..Amazing! looks like the brakes with trans clutching will be working.

 

[DMiller]

Try a Google Search under Michigan p/n xxxxxx and see what pops up. May end up scrounging a yard as General Gear for the springs and seals rings. I got lucky and a Hydraulics shop matched up Trans piston seal rings by dimension.

 

[kshansen]

Just curious what is the width of the seals and what is the bore of the housing they go inside? Also what material are they? Steel, rubber, or some kind of plastic? Just wondering if a piston ring out of an engine would work?

 

[Burnt.Fingers]

Ken, the inner drum hub sealing rings actually look like small hook style metal piston rings, minnpar had those.
They seal the clutch drum to the bearing cap and allow pressurized oil into to the drum to move the piston, I'll have to check the bores to see if the rings wore into the caps when I get it all apart again.
The clutch piston seals inner and outer are a typical lip style hydraulic seal that seals the piston to the drum.
I'm sure as a last resort I can spec them out by dimensions, I'm trying to avoid that, why reinvent the wheel if someone has them out there under the Clark part#s
The clutch release springs might be the same situation if I cant locate a source by the Clark part# or find used, I'll have to spec them out.

So far overall it's going great, pretty near as expected working on a 60 year old machine.
I've had plenty of time to clean and prepare while beating the bushes online for parts.

 

[kshansen]

Ken, the inner drum hub sealing rings actually look like small hook style metal piston rings, minnpar had those.

The clutch release springs might be the same situation if I cant locate a source by the Clark part# or find used, I'll have to spec them out.

On those springs not sure what might be available but if you can fill in some of the spec's for the ones you need I could check to see if Cat might have something close enough to work. I'm thinking OD, length and wire diameter would be the most critical information. Below is the chart for attributes I can put in and do a search:


I think if at least close would work as long as you either use a full set in one clutch or maybe alternated new and used ones in the clutch to keep things in balance.

 

[Burnt.Fingers]

There are spring suppliers that can spec out the compression style springs exactly how you described. OD, ID, wire size, free length, solid height and a few more fields with regard to rate and load at height.
I'm not quite there yet as far as exhausting all possible sources to find the original springs but it very well might come to that.
I was checking out Lee spring earlier in case I have to go that route.
https://www.leespring.com/compression-springs

One clutch pack was in excellent condition with all springs intact.
I'll go measure one up!

 

[Burnt.Fingers]

Heres what I have for spring measurements.
I'm going to keep beating the bushes for new original springs as I'd prefer to have the original parts and not chance an error in spring selection that may effect the clutches engaging or disengaging.
The springs sit between the clutch drum piston and the end plate, 10 are spaced evenly around the steel clutch disc external teeth there's a check ball that bleeds off the drum pressure when the control valve shuts off that clutch, the springs assure that the discs are instantly no longer locked together and help immediately bleed off the fluid in the drum.
When the clutch is engaged the pressure has to overcome the 10 springs to lock up the discs.

OD- .250"
ID- .141"
Free height 1.5"
Solid height 1"
Wire size. 0525"

 

[DMiller]

Standard Rockford design
I would seriously look to a yard and grab a spare old trans
Parts for these are getting harder to come by where a spare becomes a piggy bank of savings.

 

[Burnt.Fingers]

I would seriously look to a yard and grab a spare old trans

Have you seen what they're asking for a whole transmission? I can buy another complete loader for that.
Which brings me to my next point...I actually bought this loader for parts!
It's in such good shape other then the transmission that I decided to restore it and now dont want to part out my original loader either because it's still working fine..okay that settles it...I need one more!!

 

[DMiller]

Lo and Behold the addiction lurches forward
Welcome to the land of yellow iron affliction!!

 

[kshansen]

Not sure if this one would work it's a little bigger on the OD, that 7.69mm would be 0.302 inch compared to the 0.250 inch you quoted. Other dimensions are pretty close!

Cat price shows as $5.23 each.

Just might have to buy a parts machine to fix that parts machine!

 

[kshansen]

Have you seen what they're asking for a whole transmission? I can buy another complete loader for that.
Which brings me to my next point...I actually bought this loader for parts!
It's in such good shape other then the transmission that I decided to restore it and now dont want to part out my original loader either because it's still working fine..okay that settles it...I need one more!!
View attachment 223623

Now that I see that picture many years ago I recall we had one at our quarry for a short time. Don't recall where it came from or where it went, good chance it ended up on Stump Road! One has to be smart enough to not reach out the side windows while moving the bucket arms on those. Have to wonder what the safety people would say about that thing!

 

[Burnt.Fingers]

The clutch discs I need showed up today!
They look & fit perfect.
I started on the bodywork seeing how I'm waiting for parts, there's plenty of sanding to do on it before it gets new paint.
Have a nice holiday weekend everyone.

 

[Burnt.Fingers]

no leads on the rest of the transmission parts,
Still hunting for clutch release springs and clutch piston seals.
In the meantime, ive been sanding and doing bodywork,
I'm almost ready to put a fresh coat of paint on.

 

[Burnt.Fingers]

The first 2 gallons disappeared quick.
1 more gallon will do the cab, side covers and trim it out nicely.

 

[Burnt.Fingers]

Still hunting for transmission parts, I cleaned out minnpar of everything they had that I needed.
have sent off 100+ messages to various related heavy equip/transmission companies inquiring about the parts, most just give up quick and say not available.
I did manage to find some more parts at JPC transmission service located in Aspropirgos, Greece
they have the last 2 outer piston seals needed,2 inner seals, all 8 hub sealing rings and some good used clutch release springs, not sure how many at this point, they're still looking.
pricing is excellent and even with the international shipping will be a good hit when it all shows up.

In the meantime still cleaning, painting, wiring, etc

 

[Burnt.Fingers]

Making a little progress on the transmission.
Have all the seals and o-rings from JPC transmission in Greece and minnpar.
I'm ready to pull the trigger on clutch springs.
Danny Smith in Marcellus Ny said he has them.
I located 2 other sources for the springs, but it will cost considerably more.
Imolaparts in Italy has the oem springs ready to ship.
I spoke with Midstate spring in Syracuse. Ny they will manufacturer them, all I have to do is bring them a sample and cover the engineering and setup fees.
In the meantime made all the new gaskets and I'm flushing out the case to be sure there's nothing in there that will tear up the new clutches & seals.
Getting closer!

 

[Burnt.Fingers]

Transmission fully assembled and ready to paint, then re-install.
New clutch discs,steel discs,seals,orings and gaskets.
I'll know soon enough, but my gut feeling tells me this loader is going to have power to the wheels now like I've never seen before.

 

[Burnt.Fingers]

Almost there! ...jeez time flies when your having fun..been a few months rebuilding the transmission/ restoring the machine, mostly spent looking for transmission parts and buying paint to sling.
I'm half way threw the 4th gallon.
Few more things to connect up before I can fill up the transmission, bleed the brake valve,
get it off the stands and back on rubber and she'll be ready to fire on all 6.

 

[kshansen]

Dam! that is going to be looking better than it did when it left the factory? Are you actually going to let it touch dirt once it's done?