TR4/4A TR4A Through 6 Diaphragm Clutch

[TRDejaVu]

Original pressure plate, not aftermarket.

Does anyone know the wear specs for the pressure plate; actual surface thickness as well as allowable wear on the spring fingers?

Do they wear out?

What goes wrong on them?

Thanks

 

[eschneider]

Even without wear on the fingers, the springs fatigue and get weak, reducing the clamping force on the disk.

I can't imagine re-installing a pressure plate with any measurable wear on the fingers. Maybe just me.....

 

[tdskip]

I may be missing something here, but with all the work involve to get / get back to this point why mess around with it?

 

[martx-5]

I may be missing something here, but with all the work involve to get / get back to this point why mess around with it?

Because there have been a mess of incorrect pressure plates floating around out there, along with lots of horror stories to go with them.

Edit: This may be of interest...

 

[HerronScott]

I'm guessing he's read the horror stories about TR6 clutches and is trying to avoid that by using an original diaphragm. I think you mentioned that on your TR6 clutch that you recently installed that the engagement was stiff and either on or off for example.

Scott

 

[TRDejaVu]

tdskip, normally, I would agree with you completely, but on this it's because of what Art said above.

I know that there are different schools of thought on this https://www.vtr.org/maintain/clutch-laycock.pdf, so I want to see how feasible using an original diaphragm pressure plate is. I obtained one in a parts job lot that looks to be in good condition, but I would like to know that it's OK, hence my inspection and measurement questions.

I also have a TR4A flywheel that looks to be in excellent condition as well as a very lightly used 3 point pressure plate from that job lot.

I am trying to decide whether to go to the TR4A setup or stay original. I won't know how my flywheel looks until I pull the box, but the starter doesn't always catch so I suspect some starter ring damage.

 

[TRDejaVu]

Anyone used rebuilt ones from Fort Wayne Clutch? They have top feedback and the current eBay pic (item # 180515752483) seems to show the OEM style diaphragm finger setup rather than the aftermarket version.

 

[PeterK]

I know it's mixing apples and oranges, but for my HVDA 5-speed, I used the AP TR6 diaphram clutch plate with no ill effects. Granted, the HVDA uses a completely different t/o set-up but with the McLeod hydraulic t/o, it's good to go.

 

[HerronScott]

Anyone used rebuilt ones from Fort Wayne Clutch? They have top feedback and the current eBay pic (item # 180515752483) seems to show the OEM style diaphragm finger setup rather than the aftermarket version.

Never heard of them but I asked them what they did to the diaphragm and here's their response.

HI SCOTT , ANY WEAR CAUSED BY THE THROWOUT BEARING IS GROUND OUT ,THE DIAPHRAM THEN IS TESTED FOR PRESSURE, IF IT MEETS SPECS
WE USE IT . NEW DIAPHRAMS ARE DIFFICULT TO FIND, GIVE US A TOLL FREE CALL 1-800-258-8243, ASK FOR SCOTT OR MIKE
THANKS FRANK

Not sure why they think new diaphragms are hard to find....

Scott

 

[TRDejaVu]

So they base diaphragm wear on a target pressure as opposed to a wear allowance. I wonder how far above a normal pressure range that they test it to? I will drop them a line as well.

Anyone have any sort of overhaul manual that gives a wear allowance on this?

 

[MichaelG]

A few years ago I read all the horror stories when I was evaluating what to do with my 4A clutch. Please note that The TR4 does not require any constant pressure on the throwout bearing, extra springs, Gunst bearings to prevent the throwout bearing from squealing, selecting the right pressure plate to make all of this work, etc.. Just set the clearance on the slave cylinder push rod and that's it.

In the end my solution was the Magic Clutch kit from TRF..performance and feel is excellent, and it comes with the heavy duty Toyo bearing so it turned out to be the right decision in my case. NFI of course.

 

[hondo402000]

glad it worked out !!!

 

[TRDejaVu]

Here is the response I received from Fort Wayne Clutch to questions about allowable diaphragm finger wear, plate wear and testing.

"The rebuilt kit you see on Ebay for $119.00 is a Borg & beck clutch and has a new diaphragm in it, The diaphragm is riveted into the cover, the pivot ring has a 5 3/4" diameter. The plate would have less than .015 ground off during resurfacing. The diaphragm pressure would be a little heavier than an OE Laycock style would be.

We also have a new Borg & Beck pressure plate and disc available, it is a different style than the rebuilt, the diaphragm is crimped into the cover, and the pivot ring diameter is 6 3/8". The pressure on this clutch is even heavier than the rebuilt.

The spring pressure tester we use shows a high pressure, and a leveled pressure. The high pressure indicates the initial force required to push the diaphragm from the top of the pedal stroke to the released position, and the leveled pressure would be the pressure required to hold it in the released position.

The pressures are:
Rebuilt Borg & Beck 225 - 400
New Borg & Beck 300-575
OE Laycock 175-425 (taken from some old notes on file, and i can't confirm this one.)"