Model A Center & Front Main Square Head Bolts

[old28]

Motor question from a new dude to the model A motor. Started to disassemble my model A motor and ran into the square head bolts that hold the front & center main bearings. Do they take a special socket to remove? Where can I find the correct setup to use?

[DaWizard]

My motor has Crown nuts with cotter pins for all 6 main bearing bolts. You might look around for an 8 pointed socket, or if you have an OLD open end wrench you could just grind down the sides to fit. They do make 8 point sockets, just not cheap.

Turn the motor over and check from the top, those square bolt heads are on the bottom, right?

[Dick Steinkamp]

Originally Posted by DaWizard

Turn the motor over and check from the top, those square bolt heads are on the bottom, right?

The square head bolts go in from the bottom on the front and center mains and from the top on the rear main.

You need a 9/16 square (8 point) socket to hold the bolt heads on the front and center main. The rear main bolts heads are held by the rear of the block.



$6 at Sears (Craftsman) or borrow one from a buddy or the local club.

[VFRhugh]

I bought a used snap-on off eBay for less than $10 delivered. I'd never heard of an 8 point socket before I bought my A.
Hugh

[old28]

RFRhugh, Dick Steinkamp, DaWizard -- Thanks guys for the help and information. Saw a few on Ebay, called my local Tool supply store and they had one for $7.50. Will pick it up tomorrow and keep on with the build.

[PC/SR]

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Bratton has the socket, #8951. You might also think about getting their replacement main bearing bolts, which are excellent. #8950 Your old bolts probably have very little "stretch" or spring left in them.

[Tom Wesenberg]

Also notice the little tits on the heads of the main bolts. They should face straight in or straight out so the cotter holes on the top end line up for easy installation of the cotter pins.

[Marvin/TN]

Sears use to carry them, might be a good place to start, or maybe one of the tool trucks that make the rounds of body shops, car dealers, garages, etc. Find out when they make their rounds or how you can get in touch with one of them.

[CarlG]

I picked up a whole set of 8 pointers on eBay.

[Tanglfoot]

I just hammer an old 5/8 socket on to those old square heads to remove them and when reasembling the motor I use Snyders grade 8-1/2 bolts and nuts with 3/4 hex heads cost $36.00 no problem, no need for split pins. Nylock nuts may help with insomnia.

[katy]

Nylock nuts may help with insomnia

Tried them once, didn't help w/the insomnia, sure was rough passing them the next day.

[old28]

Thanks to all that replied to my thread/question.

I used Tanglfoot idea to remove them, no problem. I will put in a new set of grade 8 from Bratton or Snyders when it goes back together.

[Chuck Sea/Tac]

I just went down in the shop and a 12 point 5/8 box wrench goes on perfect. ( didn't have any 12 point sockets close by. As I recall I figured this out after buying a set of 8 points.

[Afordman31]

The 8 point sockets work well on the transmission fill plug also or any pipe plug with a square head.

[old31]

Originally Posted by katy

Tried them once, didn't help w/the insomnia, sure was rough passing them the next day.

You must have had some bad lock nuts. Mine ususally stay in forever.

You might want to try them again and wash down with some Locktite.

[Jim Brierley]

Just hold the square-head bolts with an open-end wrench and use a 3/4 socket or box wrench on the nuts. The socket will need to be shortened to get on the nut in the valve chamber.

[old28]

All six main bearing bolts are out. Will install new grade 8 bolts and nut when the motor goes back together. Thanks for all the ideas.

[5window]

Originally Posted by old28

Thanks to all that replied to my thread/question.

I used Tanglfoot idea to remove them, no problem. I will put in a new set of grade 8 from Bratton or Snyders when it goes back together.

I have always been a fan of using the correct tool for the application-especially when I get to buy a new tool. What was your fallback position if jamming on a socket rounded off the heads and didn't work-as well as screwing up the socket?

[V4F]

8 point 9/16s

[Y-Blockhead]

Originally Posted by 5window

I have always been a fan of using the correct tool for the application-especially when I get to buy a new tool.

That's what I'm talking about. I even have a Special Tool Box now just for my Model A Tools.

In fact I just asked Mrs. Claus for an Engine Stand adaptor for Christmas. She wraps my tools and lets my grandson 'give' them to me.