Update-problem resolved: Calling trans experts
 

Doing final assembly on a #78 case 3 speed. Had new oillite bushings installed and the they were too oversized to permit the cross shaft for throw out bearing fork to go through.

Re-read Mac VP's book and he stated this could be a problem. Followed his trick of filing the slot to open them up a bit.

One side worked, the other is still super tight. I even found some old NOS Ford bushings. One side went well, but the side with the clutch arm is still not going through.

When I put the shaft into the case without the bushing, the hole seems concentric and there is no obvious reason for this to be happening.

I even tried a different shaft and same thing occurred.

When I fit the bushings to shaft out of the case, I can see the amount the shell casings need to be opened, I carefully filed, reinserted the bushing and tried again. The same tightness keeps happening.

Any thoughts on what the problem could be?

Thanks,

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

You need to ream them.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Ugh. OK.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Since I'm not long on reamers, I have used a brake hone in cases such as this. If you're careful and keep checking, it usually turns out fine. If you do make a mistake, bushings are a lot cheaper than reamers

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Tub,

I started with a brake reamer. Maybe I wasn't patient enough, but it seem to be removing enough material. I had the tight side going in & out, checking, etc. for approx. 30 min.

Thanks.

Tim

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

I was taught that bushings pushed into a hole become slightly hourglass shaped, especially thin ones. On something like the bushings in play here probably not that critical but when really important, a shaft that forces the hourglass shape to make the hole more cylindrical needs to be pushed through. Case in point, look at the KRW set that puts the thin sleeves into a block.
I always hone the bushings to fit the clutch fork shaft after installing them into the trans case.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Strange. Brake hones are intended to cut cast iron wheel cylinders; bushings should be softer and therefore easier to cut. What did you use as a lubricant?

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

"Grandma's salve" ?

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

I use this stuff for the finale fit, but you gotta be able to force it in first. https://www.modeltford.com/item/TIMESAV-Y.aspx

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Gibbs oil.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

I'm going to do some measurements, but it looks like the one bore in the case maybe a bit messed up causing the bushing to distort. I need to take the gears out anyway, so if that's the case, I'll run a Sunnen through the holes to true them up and then do the bushings as well. More later and I welcome any other thoughts, tips.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

GB and I have both had luck with a dowel slotted for a length and wrapped with emery cloth. With kerosene as a lube, they cut really slowly. (The chips look like they could be used for pigment in paint.) If you wrap the emery so it's loose in the bushing, you can unwrap a bit of it and put some paper In there to increase the OD of the emery a bit to tighten it up. It would probably be best is the dowel continued into the other bushing to hold things in line. You could wrap that other end with paper or whatever to get a nice fit in the other end.

https://www.fordbarn.com/forum/showthread.php?t=167244

I also used the process to hone pedal bushings.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Thanks, Pete. I'll try that as well. I made a metal rod with a slot for emery cloth slots to be able to placed in it. Of course, I can't find at the moment. LOL!

So the shaft I have is, I believe, NOS and measures .875" (7/8") OD. The holes in the trans case measure .925". I'm thinking there is an issue with the hole where the arm mounts. It seems like maybe it's not true. Not sure that would matter, but I'm think that may it since the other works when the bushing the is fit.

This is so frustrating since it's such a simple job, yet it has taken me all day.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Thanks to Fred (Barnfind08), he helped me figure it out. Checking against a straight edge, the shaft is bent. What a kick in the pants. I never thought that could be it until he mentioned it.

Thank you all for you input. Next time, a new shaft, checked to fit and bushings honed to size. Moving forward.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

The dowel theory, or just a smaller shaft with sandpaper is good because you are doing both bushings at once, making them true, as they should be. While these bushings are not really much of a "moving part" that needs to be precise, if they are true they will last longer

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

I always burnish split bushings now, just like connecting rod bushings. Once I started doing this I no longer need to hone or polish the throwout shaft bushings once in place. The bushing don't seem to hone very well because of the impregnated graphite to act as a lubricant. Good Luck, Paul

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Hi Paul:

Makes sense. What do you use to burnish the bushing?

Tim

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

A slightly undersized shaft to "roll in" the bushing after pressing.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Ordered some today. Thanks for the tip.

Re: Calling trans experts: Issue with bushing sizing for throwout fork shaft
 

Ordered some today. Thanks for the tip.