Adding a second thrust plate pin

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Model T Ford Forum: Forum 2016: Adding a second thrust plate pin
Top of pagePrevious messageNext messageBottom of page Link to this message  By Charles Weisgerber- Vancouver WA. on Thursday, December 08, 2016 - 09:26 pm:

I'm in the middle of rebuilding my rear axle and I was thinking of adding a second thrust plate pin to the left side differential carrier. The large end of the replacement pin measures .0275. My question is...What size of drill would I need to drill the correct size hole, one that would allow for the proper press fit of the pin?

Any help would be much appreciated.

Charles


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry Kramer on Friday, December 09, 2016 - 09:03 am:

I would try a test hole into something similar with several different size drills.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Daron - Brownsburg IN on Friday, December 09, 2016 - 09:31 am:

Buy the replacement pins and measure the small end before you drill.


Top of pagePrevious messageNext messageBottom of page Link to this message  By JD, Wichita, KS on Friday, December 09, 2016 - 10:20 am:

I think you added an extra '0'.
They are .275" or so. Maybe .280"
I think I used an "I" drill bit (.272"), chamfered the pin a little and hammered it home.

I don't know if you can add a second one, as there probably isn't iron there to drill the hole on the other side?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Friday, December 09, 2016 - 10:32 am:

You can add a second pin to one side of the differential, but not the other. So you can end up with two pins everywhere except the one side of the differential shown above. I just drilled and added a second pin in my rear axle rebuild. But I do not remember the size I used. Ill try and look at the chart today and see what it was. The hard part is getting the depth right.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A Bartsch on Friday, December 09, 2016 - 12:42 pm:

What exactly is the benefit of adding the second pin? jb


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, December 09, 2016 - 12:56 pm:

Would keep the steel thrust plate centered so it does not wear the flange. The brass/bronze plate however would still be floating and can still wear the flange as can be seen with the housing on the right. The axle housings already have two pins each. In order to use two pins on the side shown, you would have to drill a hole for the pin in the steel thrust plate which I think are hardened.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Friday, December 09, 2016 - 04:10 pm:

Charles. I used NOS original pins that measure 0.280. For them I used a letter drill bit "J" (0.277). If your repro pins measure 0.275 I would use a letter drill "I" (0.272) as JD mentioned above. That should give you the same 0.003 press fit that I had with my NOS pins. The 0.003 press fit worked fine for me. After you get the pin installed, I would still "stake" the area around the pin with a blunt punch. That will "tighten" the pin up some more and also make sure the area around the pin is slightly below the steel thrust plate. Some of the new repro thrust plates fit tight around the pin or have no chamfer around the hole. I had a little problem getting the new steel thrust washers to "sit flat" and not "rock" at the pin area. After I worked the area around the new pins with the blunt punch and also a small file to remove some small "burrs" everything was OK. If the thrust washers have any rock at all it can "play heck" with your end play measurements, and give a misleading end play setting. One or two thousands per plate adds up really quick when you are trying to achieve 0.005 total end play. have fun and be safe Donnie Brown ...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charles Weisgerber- Vancouver WA. on Friday, December 09, 2016 - 09:49 pm:

Thanks everyone I was able to get the second pin installed perfectly .

Donnie, The pins did measure 0.280 and not 0.275 as I had stated earlier. Interestingly I had the same problem as you did with the thrust plate rocking. I used the same methods you did to solve the problem.

Another issue that I had was the fiber washer used to set the axle end-play between the axles. It was too thin, which I guess is common. Rather then mess around with one and a partial I machined a one piece example out of brass.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Friday, December 09, 2016 - 10:33 pm:

Charles The fiber washers are almost always too thin. I just sanded 2 of them down to I believe 0.044 each for a finished total of 0.088. I believe the repro washers are 0.078 which was 0.010 too thin. It would be nice if there was a fiber washer set available with washers 0.070 to 0.095 in 0.002 color coded increments. :-) :-) That would cover most applications.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, December 09, 2016 - 10:40 pm:

Up there with upper drive shaft bushings that only come in one size. Too bad they can't make and sell ones for undersized drive shafts.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charles Weisgerber- Vancouver WA. on Friday, December 09, 2016 - 10:45 pm:

Yes Donnie and Mark, that would be nice wouldn't it...:-)


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