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#2486271 - 04/21/18 11:37 PM 727 rebuild questions, diaphram spring and wave springs
crash520 Offline
member

Registered: 10/26/13
Posts: 185
Loc: Brisbane Australia
Gents,
I have two wave springs, one has a large wave in it the other has a slight wave in it, which one is installed on the rear drum diaphram spring? Im guessing the large wave spring goes agains the belleville spring and spacer, the flat/selective spring goes on top of the rear drum clutch pack and the small 'wave' spring goes on the front clutch pack

Also, I have a piston that has part number 2124834 in the rear drum, with the old style belleville spring installed I can move the piston retainer (input shaft) in and out of the rear outer retainer by 0.045", that is there is a gap of 0.045" between the belleville spring fingers and the piston, is this ok? and if not how can it be corrected?? I would have to machine the belleville spring ledge lower and find a thicker metal spacer to go between it and the wave spring

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#2486286 - 04/22/18 12:07 AM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
crash520 Offline
member

Registered: 10/26/13
Posts: 185
Loc: Brisbane Australia
Gents, found this vid, this is pretty much my problem answered
https://www.youtube.com/watch?v=eJsRtPhlwoA&t=9s


Edited by crash520 (04/22/18 12:08 AM)

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#2486300 - 04/22/18 01:40 AM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 19459
Loc: Rio Linda, CA
Video claims the later piston isn't thicker but it is; the early 2124834 piston does measure .780" thick but the '74-later 3743623 piston measures .830". The thicker piston is needed because of the reduced cone height of the new Belleville. The later piston and Belleville were introduced to prevent the exact same failure mentioned in the video.

Use of the late piston and Bellevile along with replacing the wavy snap ring with the thickest solid snap ring (.106") makes the rear clutch a lot more reliable without the big bucks for the billet parts.

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I'm supposed to respect my elders, but its getting harder and harder for me to find one now.

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#2486304 - 04/22/18 02:37 AM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
crash520 Offline
member

Registered: 10/26/13
Posts: 185
Loc: Brisbane Australia
Thanks John, getting hold of the later piston wont be easy out here in down under land, I do have a new late model style Belleville spring from Rick at A&A, honestly it would be just as easy to grab one of his oversize pistons and be done with it, I also have a pack of his selective snap rings so I should be able to find a thick one in that pack.

appreciate you responding so quickly mate

Greg

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#2486315 - 04/22/18 04:49 AM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
crash520 Offline
member

Registered: 10/26/13
Posts: 185
Loc: Brisbane Australia
Hey John, the rear clutch clearance is set up with selective snap rings, the front clutch has a wave ring and by using various thickness steels you can set front clutch clearances, I have 5 frictions in the front and I’d like to not use a wave spring, what’s the clearance in the front clutch when a flat snap ring is used? Wave type have approx 0.075” for 5 frictions.

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#2486464 - 04/22/18 03:24 PM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 19459
Loc: Rio Linda, CA
.012"-.015" per disc is the desired clearance so .060"-.075" is good for five discs with a flat snap ring.
_________________________
I'm supposed to respect my elders, but its getting harder and harder for me to find one now.

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#2488202 - 04/26/18 10:26 AM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
FurryStump Offline
master

Registered: 10/15/04
Posts: 2506
Loc: Connecticut
I know Mr. Kunkel has forgotten more than I will know about the 727, but I just installed a new beville spring in my trans. I have the old piston and beville. I bought a “new” part number piston and compared it to my old piston. They were the same height. From reading everything I could find this is what I think happened. I think chry reverted back to the old piston height, but just used the same part number while adding a letter to the number. I have read that people would order the new style piston and it would be shorter sometimes. In that case they blamed improper machining, but I think there are three possibilities. Old style,new style and new part number machined to the old style hieght. I have read John Cope say they went back to the old style beville/piston in the newer trans. I have also read they add a letter to a part number when they supersede it. Again I am NO expert!
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#2488385 - 04/26/18 04:05 PM Re: 727 rebuild questions, diaphram spring and wave springs [Re: FurryStump]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 19459
Loc: Rio Linda, CA
You're correct, we've had this discussion before; there are examples of "new" pistons with the new P/N that are the old dimension but my measurement was taken from an original 623 piston.

In the factory list of running changes for the '74 model year they list a new "N-D (Neutral-Drive) package" that includes the new Belleville and a new piston with "an increase in the over-all height".
_________________________
I'm supposed to respect my elders, but its getting harder and harder for me to find one now.

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#2488391 - 04/26/18 04:19 PM Re: 727 rebuild questions, diaphram spring and wave springs [Re: crash520]
crash520 Offline
member

Registered: 10/26/13
Posts: 185
Loc: Brisbane Australia
Thanks Guys, I’ve bought a new billet piston to suit my set up and eliminate all clearance

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