The Ford Barn

37slantback · 09-02-2011, 10:21 AM

I searched around but came up dry. What is the bolt size for bolting a pressure plate to a 1950 flywheel? I believe it is the long style pressure plate with the 3 pairs of holes.

Thanks,
Don

Bruce Lancaster · 09-02-2011, 11:26 AM

Go to a speed shop; one of the big speed equipment companies like Mr Gasket or Moroso sells them packaged for '60's small block Ford.

book says 5/16-18 x25/64

rotorwrench · 09-02-2011, 12:10 PM

Long style is 5/16 as above. Borg & Beck types for Mercs are 3/8" and they are special shoulder types.

37slantback · 09-02-2011, 01:26 PM

Thanks Guys. I want to pick them up at a local bolt place but wanted to make sure of the size. I want to get things put together this weekend and have all bolts but those.
The original engine seems to have lost a seal last weekend. BIG puddle of oil under the old girl. I guess that was the last drive until I get the new chassis assembled.

JWL · 09-02-2011, 02:09 PM

The pressure plate clamping bolts are not something you can find at the average bolt store. The earlier suggestion about buying the special bolts supplied by your local Speed Shop was on target.

rich b · 09-02-2011, 05:20 PM

Sponsored Links (Register now to hide all advertisements)

Fixed a car for a guy once, previous owner used standard bolts and probably didn't
torque them properly. Ended up with a new pressure plate and replacement flywheel.
Correct bolts are the only way to go in this instance.

37slantback · 09-02-2011, 05:29 PM

I found some Grade 8 bolts of that size. Called the local "Speed Shop" and they said they had some bins of bolts to look through - LOL

51 MERC-CT · 09-03-2011, 08:39 AM

I had made this suggestion in a previous post (without pic's)
The 3/8"-16 x 3/4" is what the Merc. manual calls for. (suspect same method could be used for Ford bolts) The result is virtually a duplicate of original.

flatjack9 · 09-03-2011, 09:21 AM

See Bruce's answer for the Ford bolt.

Ronnie · 09-03-2011, 09:52 AM

Don't spend time cutting and making bolts fit just buy them .

http://www.google.com/#q=pressure+pl...w=1024&bih=623

R

51 MERC-CT · 09-03-2011, 09:52 AM

Quote:

Originally Posted by flatjack9

See Bruce's answer for the Ford bolt.

Have seen answer and am surpised that the bolt is only 25/64" ( .390 ) long.

GOSFAST · 09-03-2011, 12:29 PM

You really MUST use the correct bolts, as mentioned above in few replies, using the incorrect pieces will result in a "vibration" in the flywheel/clutch area!

We see this while balancing the flywheel and cover ass'y, if the "shoulder's" aren't there and the cover isn't centered, it throws off the entire balance!

Thanks, Gary in N.Y.

P.S. Below is a shot of both sizes. We choose to not use any locking washers, it's one area we use "Loc-tite". Years ago we started drilling all the assemblies for 3/8" only bolts. Not a real big deal, and one specific customer specializing in the Flatheads wanted them done this way!!

Ronnie · 09-03-2011, 02:41 PM

Quote:

Originally Posted by 51 MERC-CT

Have seen answer and am surpised that the bolt is only 25/64" ( .390 ) long.

1"

not 25/64"

R

jdl · 09-03-2011, 03:02 PM

Quote:

Originally Posted by Bruce Lancaster

Go to a speed shop; one of the big speed equipment companies like Mr Gasket or Moroso sells them packaged for '60's small block Ford.

book says 5/16-18 x25/64

My Ford shop manual says 5/16-18 x .77
part # 350433-s c&g ford parts shows them ( costly)

https://secure435.hostgator.com/~dlv...12&g=90&t=5810

jdl · 09-03-2011, 03:03 PM

It also shows using a lockwasher..

Ray With · 09-03-2011, 03:43 PM

Quote:

Originally Posted by jdl

My Ford shop manual says 5/16-18 x .77
part # 350433-s c&g ford parts shows them ( costly)

https://secure435.hostgator.com/~dlv...12&g=90&t=5810

Costly for the 6 correct bolts?? Any idea what it would cost if the Pressure plate came loose?? Thats a hand gernade if it ever sheared off cheap ass bolts.

jdl · 09-03-2011, 04:46 PM

Quote:

Originally Posted by Ray With

Costly for the 6 correct bolts?? Any idea what it would cost if the Pressure plate came loose?? Thats a hand gernade if it ever sheared off cheap ass bolts.

So true, thats why they are costly
I don't recall saying to use "cheap ass bolts"

JM 35 Sedan · 09-03-2011, 05:30 PM

I'm wondering if Roy Nacewicz has them? I gathered up two sets (12 bolts) of nice originals that I had with my collection of flathead engines and sent them to a fordbarner in New England. I can't spare any more but maybe one of the several engine gurus who post here would have some extras they could send you.

Cecil/WV · 09-03-2011, 05:36 PM

Nice avatar, John.

Henry/Kokomo · 09-03-2011, 05:46 PM

I've bought the correct bolts from Roy Nacewicz and from "Flathead Jack" Schaffer.

09-02-2011, 10:21 AM	#1
37slantback Senior Member Join Date: May 2010 Location: Spokane, WA Posts: 172	pressure plate bolt size? I searched around but came up dry. What is the bolt size for bolting a pressure plate to a 1950 flywheel? I believe it is the long style pressure plate with the 3 pairs of holes. Thanks, Don

09-02-2011, 11:26 AM	#2
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: pressure plate bolt size? Go to a speed shop; one of the big speed equipment companies like Mr Gasket or Moroso sells them packaged for '60's small block Ford. book says 5/16-18 x25/64

09-02-2011, 12:10 PM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: pressure plate bolt size? Long style is 5/16 as above. Borg & Beck types for Mercs are 3/8" and they are special shoulder types.

09-02-2011, 01:26 PM	#4
37slantback Senior Member Join Date: May 2010 Location: Spokane, WA Posts: 172	Re: pressure plate bolt size? Thanks Guys. I want to pick them up at a local bolt place but wanted to make sure of the size. I want to get things put together this weekend and have all bolts but those. The original engine seems to have lost a seal last weekend. BIG puddle of oil under the old girl. I guess that was the last drive until I get the new chassis assembled.

09-02-2011, 02:09 PM	#5
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: pressure plate bolt size? The pressure plate clamping bolts are not something you can find at the average bolt store. The earlier suggestion about buying the special bolts supplied by your local Speed Shop was on target.

09-02-2011, 05:20 PM	#6
rich b Senior Member Join Date: May 2010 Location: Minnesota Posts: 1,827	Re: pressure plate bolt size? Sponsored Links (Register now to hide all advertisements) Fixed a car for a guy once, previous owner used standard bolts and probably didn't torque them properly. Ended up with a new pressure plate and replacement flywheel. Correct bolts are the only way to go in this instance.

09-02-2011, 05:29 PM	#7
37slantback Senior Member Join Date: May 2010 Location: Spokane, WA Posts: 172	Re: pressure plate bolt size? I found some Grade 8 bolts of that size. Called the local "Speed Shop" and they said they had some bins of bolts to look through - LOL Last edited by 37slantback; 09-02-2011 at 05:54 PM.

09-03-2011, 09:21 AM	#9
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: pressure plate bolt size? See Bruce's answer for the Ford bolt.

09-03-2011, 09:52 AM	#10
Ronnie Senior Member Join Date: May 2010 Location: Canada Where it snows Posts: 2,058	Re: pressure plate bolt size? Don't spend time cutting and making bolts fit just buy them . http://www.google.com/#q=pressure+pl...w=1024&bih=623 R

09-03-2011, 12:29 PM	#12
GOSFAST Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 1,052	Re: pressure plate bolt size? You really MUST use the correct bolts, as mentioned above in few replies, using the incorrect pieces will result in a "vibration" in the flywheel/clutch area! We see this while balancing the flywheel and cover ass'y, if the "shoulder's" aren't there and the cover isn't centered, it throws off the entire balance! Thanks, Gary in N.Y. P.S. Below is a shot of both sizes. We choose to not use any locking washers, it's one area we use "Loc-tite". Years ago we started drilling all the assemblies for 3/8" only bolts. Not a real big deal, and one specific customer specializing in the Flatheads wanted them done this way!!

09-03-2011, 03:03 PM	#15
jdl Senior Member Join Date: May 2010 Location: California Central Coast Posts: 931	Re: pressure plate bolt size? It also shows using a lockwasher..

09-03-2011, 05:30 PM	#18
JM 35 Sedan Senior Member Join Date: May 2010 Location: Near Rising Sun, Maryland Posts: 10,858	Re: pressure plate bolt size? I'm wondering if Roy Nacewicz has them? I gathered up two sets (12 bolts) of nice originals that I had with my collection of flathead engines and sent them to a fordbarner in New England. I can't spare any more but maybe one of the several engine gurus who post here would have some extras they could send you. __________________ *John* *"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein*

09-03-2011, 05:36 PM	#19
Cecil/WV Senior Member Join Date: May 2010 Location: Gerrardstown, WV Posts: 2,266	Re: pressure plate bolt size? Nice avatar, John.

09-03-2011, 05:46 PM	#20
Henry/Kokomo Senior Member Join Date: May 2010 Location: Kokomo, Indiana Posts: 1,731	Re: pressure plate bolt size? I've bought the correct bolts from Roy Nacewicz and from "Flathead Jack" Schaffer.