The Stovebolt Site Forums The Parking Lot Big Bolts PTO HELP!!!

I need help with my PTO. It looks as if a piece sheered off and it is leaking. It is a Muncie PTO. I will try and get better photos of it cleaned up. The gear and shaft inside are intact and the PTO drive shaft fits nicely. I am just missing the half moon metal piece. Are there three bolts that hold the shaft and gear in the PTO (not the drive shaft)? From what I can see it looks like bolts but they are sheered/ground and just look round. The gasket is leaking badly so I made a metal plate for now and will install the PTO once I get it fixed. Here is a photo (dirty one). click on full size and then the box at the right bottom corner to enlarge.
http://community.webshots.com/photo/231809906/264651181xlDPgy

Thanks,

Keoni

ur2slo,
The half moon metal piece is called a woodruff key, you can get them at any hardware store. When the PTO driveline yoke gets worn and wobbles, it sometimes grinds the heads off the bolts and they look strange. I think if you take the bearing housing off, install a new bushing/bearing and seal it will be as good as new. You will probably have to drain the transmission first or risk getting a bath. I would bet if you did a search, you could find an
exploded view of that box (SM420), maybe even with part numbers.

Stuart.

When you clean up the PTO be sure to inspect the cut in the shaft where the key goes. These often get wallowed out and ruin the shaft. It may be hard to find a shaft for that old Muncie as these haven't been made in a long time. Look in the Yellow Pages under Power Drives for a Muncie or Chelsea distributor. Your Muncie was originally produced by Chelsea and repackeaged as a Muncie brand so either distributor would be familiar with it. I believe it was a "P" series.

Thanks guys, as always great help!

the PTO Gasket ya can get at napa for 49 Cents.. Just bought 6 of them... so many cuz sometimes a pto has to be shimmed out to get clearance on the gear its going on... The rounded off bolts are just pan head phillips 1/4 inch screws i think.. and if i remember right it just holds the seal or maybe even just packing around the shaft...those screws shouldnt be that tight or hard to get out...(vise grips, or chisel) then just replace the seal or packing.... if you cant find the numbers on the seal,,,if you just measure it...any good industrial bearing place should be able to get a seal by the size of it.. outside diameter of seal,,,and shaft size..which i think is 3/4 inch....and yeah like the other guy said the woodruff key is easy to get at auto or hardware store..... My recently acquired one is leakin a little but i checked the transmission and can still touch lube,,,so its not leakin that bad.... ill just keep an eye on it...and if its not drippin constant or runnin out..im gonna worry about fixin other stuff first... Lot of those old pto's leak a little.....

Just out of curiousity what rpm does the PTO run at and is it fairly constant like a tractor pto?

depends on what r.p.m. the engine is running. parts for older p.t.o.'s are often available at the the joint and clutch service in indy. another source in indy is called "power train service". maybe they have website with toll free #'s.

not to freak out here. thousands of old trucks have this same setup. if there are any old junkyards left out there, you should be able to find one.

pretty easy fix, really

The ratio of the PTO is dependant upon the gear it has and is a constant that is stated as a percentage of engine speed. Most of the SM420 with the single gear Chelsea ran at approx. 46 to 64% of engine speed. That is from memory and may not be correct but I used a ton of these in the 60's and 70's on SM420's and CH465's. The old hydraulic pumps were not good for anything over 1000 RPM which is where they were capacity rated so I advise 1300-1500 engine RPM as maximum.

ur2slo,
Just a thought...it isn't unheard of to drive around with the PTO engaged and not know it. Some times the handle or knob position is sort of confusing as to what is in and what is out! Needless to say you shouldn't be engaged unless you are
using the device the PTO is powering. This sounds silly, but several months ago I drove the old company truck a whole bunch of miles "real fast", and had the PTO engaged. It survived, but I couldn't believe that I could have done that. This situation would cause a marginal PTO to leak like a sieve.

Stuart.

atomarc is right. It can be particularly hard on a hydraulic pump and if the PTO is attached to a shaft expect it to come flying out from under the truck doing about a hundred MPH. I once installed a new hoist on a new chassis for a customer and showed him and thoroughly explained the PTO operation. So he paid me and I went back to work. A while later I noticed he was just driving off and KERRWHAMM..the PTO driveshaft flew out from under the truck taking a brand new muffler with it. The shaft was twisted like a pretzel. So watch those RPM's.

Again thanks for all the info, this site is the best.
I replaced the screws and put in two new gaskets and I used gasket sealent but it still leaks from arround the shaft as well as the shaft that the engagement handle attaches to. Should I pack it with grease? I did not see an internal seal around these shafts.
The PTO should be called PTOL (Prone To Oil Leaks!)

The seals ned to be replaced. Also it is not necessary or recommended to use any sealant around the PTO/transmission surface. DO NOT use grease. The PTO gear get it's lubrication from the tranmission. Just fill until you can touch the oil with the end of your finger.

Sorry to disagree with you but a properly rebuilt PTO does not leak. Best bet for you is to take it off and get it to a Power Drive dealer and have them do it.

It sounds like that one is totally worn out, to the point the seals can't keep up with the wobbly shafts. There will be either bushings or ball bearings on the output shaft, and probably sliding bushings on the control rod, with lip seals everywhere they pass through the case. Good bearings and bushings will keep the shafts steady enough for the seals to do their job.
Jerry

On the Output shaft of that pto was there a bearing,,,or just a bushing??? Probably just a bushing,,,and if there is no seal.. then the screw plate thingy might of held packing to seal it.. packing is kind of a rope type thing that as ya screw down that plate just squeezes the stuff around the shaft sealing it off... or it could have an o ring in the case sealing it off around the shifting shaft... they didnt use to many o rings back then tho... typically its just a bushing and its probably worn out.. A machine shop could make you another bushing but its probably the shaft worn too... i cant tell too good from the picture but it dont look like its leakin that terrible bad..??? do you have a puddle...or just an occaisonal drip..??? A drip you can live with,,unless ur parkin it on the kitchen carpet...hehehehe

It leaks pretty badly especially since I cleaned the 57 years of gunk off. When I cleaned the inside it looked like it had two bushings on both sides of the berrings. The shaft and key slot appeared to be good and not really worn but I have an untrained eye. I made a temporarry plate out of sheet metal to cover the PTO hole and will try and take it to a hydrolic shop to see if they can rebuild it if nescessary. I have the photos of it cleaned up and will try and post them soon.

ur2slo, what are you waiting on? There are places in HI that sell both Chelsea and Muncie. The parts are dirt cheap for these things.

Yes, it uses seals. No, it does not use rope packing. Yes, it has bushings, not bearings. Go to the Chelsea website, find thier dealer in HI and get those parts.