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-   -   Tutorial: patch repair to worn pinon splines '37 (https://www.fordbarn.com/forum/showthread.php?t=274057)

Newc 12-14-2019 06:06 PM

Tutorial: patch repair to worn pinon splines '37
 

11 Attachment(s)
OK; Some time ago I asked about my worn pinon splines [10] in a '37 diff. and got a suggestion of loctite 660. Had to get it AND its primer from Fastenal cause it is a 'hazmat.' item. Can't be normally shipped. Also found directions on U-tube. Shear pin is a custom mfg'd .255 diameter, prefitted!
First clean drive shaft splines throughly with brake cleaner. This removes the easy oils and softens the serious oil residues. Cleaned splines with towels and then fine scotch brite pads. Since drive shaft is hollow, I had it tipped. Flushed with brake cleaner and towels. Inspected driveshaft splines with flash light. All clean and shiny now. Note, you have to scrub between the splines, on both parts
Second the pinon splines. Make a 'bib' to protect the bearings. Start your cleaning.. progressively working harder to get shiny metal. Same idea clean the worn surface and between the splines. Use the scotch brites up and get a clean pad. I cut them up with cheap blades. Now the worn surface is evident, it is the power side of the splines and I lightly scratched it with 240 grit paper. Final cleaning now.
Primer is lightly sprayed on the pinon only. Drys quickly. Now apply the 660 to the evident wear areas of the pinon splines. I may have been stingy with the 660..too late now. hope for the best.
Assemble driveshaft onto pinon correctly and insert shear pin. STOP-take a break. Driveshaft should be supported to prevent angle cure of product. After two hrs + shear pin can be expanded carefully, do not hammer without support to opposite side of pin. Think of those pinon bearings.
I will not get to 'test' this repair until the chassis is driving..soooo we'll see.
Photos for all;

supereal 12-15-2019 01:59 PM

Re: Tutorial: patch repair to worn pinon splines '37
 

If the pinion splines are badly worn, it is likely that the driveshaft is too, probably due to a broken or sheared pin holding the shaft to the pinion. You might try using a driveshaft coupler. From the photo, it looks like you have a 10 spline shaft. The coupler is available from C&G as 48-4684. the 6 spline version is 68-4684. The coupler pin is 48-4607.Their phone is 800/266-0470.

Terry,OH 12-16-2019 07:46 AM

Re: Tutorial: patch repair to worn pinon splines '37
 

Loctite is a fine product, it appears your going to test it to the max. At your point of assembly would it not be better to replace the ring and pinion or the entire differential? How does the drive shaft fit onto a good pinion, is it tight? Good luck!

Mart 12-16-2019 07:43 PM

Re: Tutorial: patch repair to worn pinon splines '37
 

Hello Newc.

The problem with posting what you do is that you open yourself up to criticism from all. I'm not going to criticise, I hope it goes well. I'm always trying workarounds myself and think, oh well, if it doesn't work I'll just do it again differently.

I just wanted to offer a suggestion. If the loctite does degrade and any play reappears in the shaft to pinion splined joint, the pin will try and do the driving. It can't do that, and will snap. The pieces will come out and can cause noise or other problems.

I've had it happen a couple of times.

When I put the axle together in my roadster for the last time, I added a safety device to the pin by putting a hose clamp around it. If it breaks the clamp will keep the parts in place. I added two more clamps, one each side of the first, arranged at 120 degrees to each other to keep the first one in position and balance it out.

The second thing I did was to arrange the axle up on end with the shaft sticking straight up. I rotated the shaft and checked it for running true. I used application of weld on the shaft to pull it straight. (It was a modified 32 type tubular shaft.)

You might consider using one or both of these "tricks" to ensure a better chance of success.

I have some pics somewhere, but it's late here now and I need to turn in.

Mart.

Newc 12-17-2019 01:09 AM

Re: Tutorial: patch repair to worn pinon splines '37
 

Thanks for your input fellows; I have found this type of 'patch' in some large truck driveshaft slip spline sections so I tried it in desperation vs all 'new' parts. It'll be a yr + before it is driven. Our old Fords are 'eating' what parts we can find. newc

tubman 12-17-2019 09:17 AM

Re: Tutorial: patch repair to worn pinon splines '37
 

Good for you for trying this. It's always a good thing to be able to successfully fix something rather than replacing it. Which chemical company had the motto "Better Living Through Chemistry"? This has never been more true than now, what with glued together airplanes, glued on sheet metal etc. I have no doubt that this will probably work fine.

A case in point. When I bought my Corvette in 1987, I found it had a stripped thermostat housing mounting bolt. I could have replaced the manifold (not an easy task even back then), or try to effect a repair. I decided to try to fix the stripped hole with a "Loc-Tite" product intended for just such purposes. I followed the instructions and it seemed to work fine; the bolt took the specified torque with no leaks. Two years ago, I did a valve job on the car, which involved removing the thermostat housing. When I took it apart, I remembered my 30 year old repair. Upon inspection, the threads looked fine. On reassembly, the bolt went in fine, took the specified torque, and still doesn't leak.

I'm a believer.

40 Deluxe 12-18-2019 01:28 AM

Re: Tutorial: patch repair to worn pinon splines '37
 

Quote:

Originally Posted by tubman (Post 1832358)
Good for you for trying this. It's always a good thing to be able to successfully fix something rather than replacing it. Which chemical company had the motto "Better Living Through Chemistry"? This has never been more true than now, what with glued together airplanes, glued on sheet metal etc. I have no doubt that this will probably work fine.

A case in point. When I bought my Corvette in 1987, I found it had a stripped thermostat housing mounting bolt. I could have replaced the manifold (not an easy task even back then), or try to effect a repair. I decided to try to fix the stripped hole with a "Loc-Tite" product intended for just such purposes. I followed the instructions and it seemed to work fine; the bolt took the specified torque with no leaks. Two years ago, I did a valve job on the car, which involved removing the thermostat housing. When I took it apart, I remembered my 30 year old repair. Upon inspection, the threads looked fine. On reassembly, the bolt went in fine, took the specified torque, and still doesn't leak.

I'm a believer.


As I recall, DuPont gave us "Better Living through Chemistry".

supereal 12-18-2019 05:51 PM

Re: Tutorial: patch repair to worn pinon splines '37
 

Use only the special hardened pin to connect the pinion to the driveshaft. It is part number 48-4607. It works for both 6 and 10 splines. but the 10 must be cut shorter for the 6. $1.95 at C&G 800/266-0470


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