Rear Motor Mount Bolts

BudP

BudP

Senior Member
I pulled my May 1929 motor for a rebuild and am replacing the rubber mount pads and rear motor mount bolts with Bratton products. The rubber mics to 15/64s which is slightly larger than the 7/32" thick in the Judging Standards) and the bolts are 5/16 x 1 3/8" which is the correct length according to the Ford Service Bulletins (page 439, green book), Les Andrews Vol. I, and is the length sold by Brattons and Synders.

The bolts seem 1/8" too short and will not allow the castle nut to be turned enough so that the cotter pin hole shows without either breaking the bolt (one bolt) or stripping the threads (three bolts). I have only managed to fasten a single bolt with a cotter pin.

I have removed all paint where metal meets metal, e.g., under the bolt head and under the nut head.

I have put Kroil on the threads but that only allows me to turn the nut with less resistance which either leads to a snapped bolt or stripped threads.

I would rather use what is specified than go to Home Depot to get some grade five bolts that are 1/8" longer.

Any suggestions? Thanks.
 
I would tighten all the bolts down snug and let it sit for a while possibly the rubber might start to compress and you could get the xtra 1/8 inch,it's worth a try.
 
BudP said:
I pulled my May 1929 motor for a rebuild and am replacing the rubber mount pads and rear motor mount bolts with Bratton products. The rubber mics to 15/64s which is slightly larger than the 7/32" thick in the Judging Standards) and the bolts are 5/16 x 1 3/8" which is the correct length according to the Ford Service Bulletins (page 439, green book), Les Andrews Vol. I, and is the length sold by Brattons and Synders.

The bolts seem 1/8" too short and will not allow the castle nut to be turned enough so that the cotter pin hole shows without either breaking the bolt (one bolt) or stripping the threads (three bolts). I have only managed to fasten a single bolt with a cotter pin.

I have removed all paint where metal meets metal, e.g., under the bolt head and under the nut head.

I have put Kroil on the threads but that only allows me to turn the nut with less resistance which either leads to a snapped bolt or stripped threads.

I would rather use what is specified than go to Home Depot to get some grade five bolts that are 1/8" longer.

Any suggestions? Thanks.
Click to expand...

Damn if I didn't have the SAME problem two weeks ago! Except I used original bolts and STILL came up short by just a little bit though.

I even shaved off the "BRATTONS" wording off of the back of the rubber pads!.

If I remember right, they were advertised as the the correct thickness as original BECAUSE, if I remember right, way back when and at one time they were not and everyone was having a heck of a time just getting the engine to fit between the mounts.

Maybe we got some left-overs from years ago???

Pluck
 
I recently (last week) replaced the rear motor mount rubber (purchased from Snyder's), and used the original bolts and castle nuts. All went well; no fitment issues. Sorry I can't provide any measurements on the new pads.
 
The pads are advertised to be correct but all that I have ever used were TOO thick. There may be some correct mount pads available but you can bet that the old too thick pads are still out there and will get put off on somebody. I have had to grind the thickness down to be able to use the pads that have been sold to me. Oiling new threads on rear motor mount bolts only makes them easier to wring off or strip.
 
How about the 6 steel sleeves that fit inside the rubber. When the kit is bolted together it seems the steel sleeves should be the limiting factor for how far the nut can thread on the bolt. The steel sleeve should touch the inside mount and the steel outside plate, so if you use 6 new steel sleeves, maybe they are too long?:confused:

Also are the rubber raised areas tucked into the frame holes, and not bunching up on the outside of the holes?:confused:
 
Tom Wesenberg said:
How about the 6 steel sleeves that fit inside the rubber. When the kit is bolted together it seems the steel sleeves should be the limiting factor for how far the nut can thread on the bolt. The steel sleeve should touch the inside mount and the steel outside plate, so if you use 6 new steel sleeves, maybe they are too long?:confused:

Also are the rubber raised areas tucked into the frame holes, and not bunching up on the outside of the holes?:confused:
Click to expand...

I agree. He can't get the bolts tight enough to expose the holes for the cotter pins to enter the slots in the castillated nuts. This is also the problem that I have had.
 
Problem has to be the thickness of the rubber. Each mics 1/64-1/32 thicker than judging standards. New steel sleeves and old steel sleeves are identical in length when rust is removed from old steel sleeves. Old bolts and new bolts are identical in length. Inside rubber mount has been properly tucked into frame holes before bolts are inserted.

Not mentioned in my first post was the fact that some of the new steel bolts were not cleanly drilled and all of the cotter pins furnished with the nuts and bolts were too great in circumference for the bolt holes.

I will send an email to Mr. Walt Bratton detailing my findings. He has a very strong commitment to quality. If his review verifies my findings, this problem will not exist for very long.

Now, I'm going to shave the outside rubber mounts. The rubber is hard as a hockey puck and does not compress so it should be doable.

Thanks for your insightful and helpful comments.
 
BudP said:
Problem has to be the thickness of the rubber. Each mics 1/64-1/32 thicker than judging standards. New steel sleeves and old steel sleeves are identical in length when rust is removed from old steel sleeves. Old bolts and new bolts are identical in length. Inside rubber mount has been properly tucked into frame holes before bolts are inserted.

Not mentioned in my first post was the fact that some of the new steel bolts were not cleanly drilled and all of the cotter pins furnished with the nuts and bolts were too great in circumference for the bolt holes.

I will send an email to Mr. Walt Bratton detailing my findings. He has a very strong commitment to quality. If his review verifies my findings, this problem will not exist for very long.

Now, I'm going to shave the outside rubber mounts. The rubber is hard as a hockey puck and does not compress so it should be doable.

Thanks for your insightful and helpful comments.
Click to expand...

And maybe that is part of the problem that the new pads just may be soemwhat harder than the originial pads???

Pluck
 
Bud,
I noticed you dropped me a PM. I sent you a reply... I just measured an original rear inner rubber piece, Firestone molded A-5092 very pliable yet piece and it measures from .210-.215 thick. I don't have a brattons unit in my stock right now but I believe last I checked it was right at that.... or close. Barring the fact of compression and age... I have replace many of these and the older harder thicker rubber was a problem but honestly I can't remember the last time I had one I coulden't get assembled. Yes, you may only have a thread or so start but it should be OK .
To me the worst part is getting the mounts in and lined up/all flywheel housing bolts in when replacing rubbers in a car where the engine is installed. A service operation that sometimes goes smoother than others.

Let me know how you fare and what your measured caliper dimension is on the rubber you have.

Larry Shepard
 
Larry,

Many thanks for your thoughtful response. I have replied to it but just so readers of this forum understand what I found, my L-shaped mold measures .246 on the hole side of the L and my outside rubber measures .251. So, I think I have found the issue. I do fit the L shaped rubber into the holes first, then add the cylinders, then insert the bolts so I believe my process is correct. My original rubbers were too disintegrated to get a consistent measurement from so my comparison unit became the "Restoration Guidelines and Judging Standards.

I work alone so placing the engine and lining up the flywheel housing bolts should be interesting: fortunately I go slow, work safely and have a lot of patience.

Many thanks,
Bud Pratsch
 
I just opened a package of new Snyder's rubber mounts. The inside pad measures .200" and the outer pad measures .218". They are very soft and pliable.
 
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