I just installed new bushings in my 39 style trans case for the clutch release shaft. Do these need to be reamed at all? If so what size reamer do I need to buy? Does the same apply to pedal bushings?
Does your shaft fit in the bushings without reaming? If so, does the shaft rotate freely? Is the shaft bent or worn?
The shaft fits but it is very tight, when I engage the bearing the spring doesn’t have enough tension to return it back. Shaft is original but in good straight condition
Shaft should be 7/8th inch so you would need to clean out the bushings so the shaft moves freely but is not sloppy.
Commonly the bush running areas on the shaft are worn, especially on the lever end. If these are worn , reaming the bushes to slide the shaft into position will make it loose in the bushes. Is the shaft back to its proper position when you’re testing it?
I just used a brake cylinder hone to do kingpin bushes on a Grey Fergie tractor. They were just too snug to turn freely so a bit of time with the brake hone and good as gold. May not work in your application but worth a try before buying a reamer.
We nearly always have to fit the bushings for a proper fit against the shaft. I’d say every bushing requires either reaming or honing to get the fit we want……snug enough that we can’t feel any wobble or sloppiness to the clutch shaft, yet loose enough that the little release bearing return spring can do its job. The fit will change a bit depending on whether you are reusing the old clutch shaft or using a brand new shaft. We used to use a small wheel cylinder hone to open up the new bushings, but we changed to using a quality adjustable reamer a couple years ago. One size reamer will not allow for fine tuning the fit we want, especially when reusing the old shaft. The adjustable reamer has made this chore go so much faster for our shop. New bushings will almost always have enough wall thickness to require you to adjust the internal fit to the shaft, particularly after you drive the bushings into the case. Think about replacing the clutch release shaft…..they are often pretty worn where the bushing rides, especially on the left hand (drivers side). Also the shaft can get bent slightly during the process of driving out the 5/16” pin that secures the release fork to the shaft. The current price for the new shaft is about $20 so it won’t set you back a lot.
While a reamer will get things to size, its sometimes difficult to get them going straight into a hole. When set up properly, they will put a specific size hole in place. Problem is that it only puts that exact size hole and if its correct for your needs.........everything is fine. It can be that your shaft is maybe a little larger (say .0005) than the reamer and you still have a tight fit. I would use either a small brake cylinder hone or a small flap wheel. My preference would be the small flap wheel if you can get the size you need. Then just run it thru the hole for a moment to clean the inside of the bushing. Test fit the shaft. If its still too tight, hone it again.....etc. This will give you the best fit as the flaps will take only minute bites at the apple. The other side of this is that you may be able to mount the shaft in a drill press and polish the shaft with emery paper. Not sure if this is possible with your shaft, because I don't know if it has fingers or something in the way. The general idea here is that polishing/honing takes a much smaller "cut" and allows you to work till you have a perfect fit. Reaming makes a specific size that can be either better or worse depending on manufacturing tolerances of the parts you are using.
I use this stuff for finish fitting bushings and babbit bearings. Its like valve lapping compound, but it will disintegrate to nothing if some is left behind. look at the model T vendors, you can buy a smaller, cheaper container. https://www.shopnewmantools.com/products/timesaver-1-lb-yellow
The adjustable reamer can be made to take a zero cut or incremental cuts up to several thousandths over the basic diameter. That lets us fine tune the amount of bushing material taken out to get a nice fit. Of course, it’s not cost effective to spend the money for the adjustable reamer if you were only going to work on one or two transmissions. We LOVE this tool.
OP 's question was ,"do these ( bushings) need reaming , first thing that popped in my head was , " well yea, if they're too tight " ....LOL
My low buck, one time use, method is to use a 3/4 inch dowel rod about a foot long. Cut a piece of 400 grit wet/dry sandpaper to wrap about 1.5 wraps of the dowel, about same length of dowel. Wrap, wet, and ream until you like the fit.
Every press fit bushing gets squished a little on installation. I always size them after install. How much bigger than what passes through them depends on the purpose. A clutch pivot and a wrist pin would obviously have a different specification. Hone a little. Check. Hone a little more. Check. Repeat as necessary until there is no detectable play, but it moves freely. Remember, when it gets hot, it will get tighter. If the shaft is indeed 7/8", then a Lisle 10000 Brake Cylinder Hone should do the trick. It can be had at most good auto parts stores.