Author Topic: Pressure Plate Refurb  (Read 147 times)

chetbrz

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Pressure Plate Refurb
« on: August 29, 2018, 02:53:39 AM »
I found some enthusiasm today and decided to refurb one of the older style pressure plates found on the Q & U.
The picture below is the one I started on.



The plate itself had a lot of surface rust but no deep dings or scrapes.  So I marked the housing and arms with tie-raps and dissembled the pressure plate.   I used three 'C' clamps to compress the plate for disassembly.  I cleaned and painted the surface areas with heat resistant engine enamel.



I resurfaced the plate by lapping off the surface rust and glaze.  Only took off about 0.006 of an inch.  This left a good thick plate surface.  I used the new springs from my old pressure plate because they were in fact the correct springs.  Below is the assembly using the 'C' clamps to compress the plate so that the arms can be installed.



Below is the finished product.  I think a much needed improvement over my original. 



I am going to use this pressure plate in my car for two reasons.  I like the way it came out and it is the correct plate for my 29U.

Working my way back after some disappointing events.  Motor is back in the shop. 








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Articifer Tom

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Re: Pressure Plate Refurb
« Reply #1 on: August 29, 2018, 03:33:22 AM »
I agree ,nice looking job . Other can always be sold .

rwollman

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Re: Pressure Plate Refurb
« Reply #2 on: August 29, 2018, 07:21:34 PM »
Chet- was curious if you happened to measure thickness of refurbed pressure plate against the one that disintegrated on you

chetbrz

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Re: Pressure Plate Refurb
« Reply #3 on: August 29, 2018, 11:18:03 PM »
Chet- was curious if you happened to measure thickness of refurbed pressure plate against the one that disintegrated on you

The old plate was a little over an 1/8 thinner than the one I just did.
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rwollman

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Re: Pressure Plate Refurb
« Reply #4 on: August 30, 2018, 03:06:54 PM »
well that at least .125 thinner - makes sense.

chetbrz

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Re: Pressure Plate Refurb
« Reply #5 on: August 30, 2018, 04:47:24 PM »
well that at least .125 thinner - makes sense.

I think like the brake drums.., these items were never designed to be resurfaced.  I think you have a much better chance resurfacing the pressure plate than you have resurfacing the brake drums.  I think the key word is to be ultra conservative and do as little harm as possible.   There was a noticeable visible difference between my old and new plates.  The area from the bottom of the arm post to the surface of a new pressure plate is only about 1/4"  (0.250).  The plate I refurbished was 0.191 when I started and ended up at 0.185.  I would estimate .065" under original size.  I would guess that this is not the first time my new plate was been refurbished.

The old pressure plate would have worked if the arms didn't come in contact with the bearing fork which caused the plate to crack across the arm post.  If we can learn anything about our cars from this mishap it is; never run the engine without the transmission unless you remove the pressure plate and clutch. In my opinion.
 


The thickness of the metal from the bottom of the arm post to the plate surface on the old pressure plate was approximately 0.065".  If you add this to the 0.125" difference it equals 0.190.  Approximately where I started with my new old plate.

Chet...
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rwollman

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Re: Pressure Plate Refurb
« Reply #6 on: August 31, 2018, 12:30:30 AM »
I think your statement regarding the brake drums to be very correct - the design and heft of these drums makes it practicably useless to turn.  Any heat at all will distort them and the thinner they are the worse it gets.  Any news from your engine builder yet on what happened to the crank and/or rod(s)?

chetbrz

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Re: Pressure Plate Refurb
« Reply #7 on: August 31, 2018, 02:13:42 AM »
Nothing yet.
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