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80fbody
mopar


Reged: Oct 25 2006
Loc: Mass.
727 - Air Check - Not Going Well?
      #7861262 - Sun Sep 22 2013 05:20 AM

Been trying to get this BB 727 together, 1st build as I mentioned in a previous post. I'm just not happy with the "air check" on the front pack. I've tried it just on the pump & now twice bolted together. I just pulled it apart & changed the inner seal on the pack again. Lips are down.

At about 35 psi the rear pack has a good "thump" & then bleeds down. Now the front does have an okay "thump" but holds absolutely no pressure. It comes out as fast as it's going in. Tried to take a video of the "air check". Never tried to video with the phone before.

I did replace the complete pump (rebuilt unit) with the hopes it was just something there but no luck.

Would you tear it back down or close it up & hope it's ok?

--------------------


1980 RoadRunner
360,4 speed,4:10
----------------
1968 Dart
451/727/4:30


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MR_P_BODY
Master


Reged: Jun 13 2003
Loc: Romeo MI
Re: 727 - Air Check - Not Going Well? [Re: 80fbody]
      #7861365 - Sun Sep 22 2013 08:22 AM

Tear it back down... you have some issues


--------------------

W-9 9.08 @ 149.6 NOW ON E-85
Mike "Raff"...(180)Watching over us
CAR IS FOR SALE


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Cheatham
enthusiast


Reged: Aug 10 2009
Loc: corpus christi tex
Re: 727 - Air Check - Not Going Well? [Re: 80fbody]
      #7861371 - Sun Sep 22 2013 08:31 AM

have you tried to prime the port with a little tranny fluid then air check it ?

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Joesixpack
master


Reged: Jan 21 2003
Loc: Joliet IL
Re: 727 - Air Check - Not Going Well? [Re: Cheatham]
      #7861380 - Sun Sep 22 2013 08:50 AM Attachment (40 downloads)

if it was me i would have a pro trans builder check it out first,its not worth it to install it and have problems, and face this sight on your back on a creeper....dont ask me how i know...

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80fbody
mopar


Reged: Oct 25 2006
Loc: Mass.
Re: 727 - Air Check - Not Going Well? [Re: Cheatham]
      #7861462 - Sun Sep 22 2013 10:41 AM

I just tried to prime the ports with ATF but no luck. Also put another set of front clutch seals in & put it back together. No change. So what else could cause a severe air leak? Couple things. I bought this as a supposed running core a few years ago. Was not in very good shape when I opened it up. Had water damage in it but did seem to clean up ok. It's stamped 3674, i believe, which I translated to a 1971 core. That's what I've been ordering parts for.

I know some changes were made around 70-71. Is there anything there that could be screwing me up? Did any sealing rings change slightly, etc? I can mic it up if you guys have any direction.


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J_BODY
Back in the saddle again


Reged: Apr 30 2003
Loc: aZLiViN
Re: 727 - Air Check - Not Going Well? [Re: 80fbody]
      #7861562 - Sun Sep 22 2013 12:23 PM

Not following you on "air checking with the pump". I've always air checked using the ports toward the top of that pict with the valve body removed.

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rickraw
pro stock


Reged: Oct 29 2010
Loc: Ambridge, Pa.
Re: 727 - Air Check - Not Going Well? [Re: J_BODY]
      #7861573 - Sun Sep 22 2013 12:36 PM

Since we can't see any of ur parts, might be time have a builder check things out. U could have nicked a seal or have installed the incorrect one. u never know.

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Joesixpack
master


Reged: Jan 21 2003
Loc: Joliet IL
Re: 727 - Air Check - Not Going Well? [Re: rickraw]
      #7861579 - Sun Sep 22 2013 12:43 PM Attachment (42 downloads)

air check

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Joesixpack
master


Reged: Jan 21 2003
Loc: Joliet IL
Re: 727 - Air Check - Not Going Well? [Re: Joesixpack]
      #7861582 - Sun Sep 22 2013 12:43 PM Attachment (34 downloads)

4 areas to air check

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dartman366
secretly desires a Big Block!!


Reged: Jan 18 2004
Loc: Mt. Vernon, Ohio
Re: 727 - Air Check - Not Going Well? [Re: Joesixpack]
      #7861993 - Sun Sep 22 2013 06:44 PM

Could of rolled a lip seal in the high gear drun during assembly, some times they can be a real bear trying to get the seal past the clutch plate/disc retaining ring groove.

--------------------
Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.


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MisterFiberglass



Reged: Jul 04 2008
Loc: WINNING - in PaRaDiSe ....Bra...
Re: 727 - Air Check - Not Going Well? [Re: dartman366]
      #7861997 - Sun Sep 22 2013 06:47 PM

I always used to use lots of ATF ....

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no, No, NO - not a vaca with the nUtTy FrUiTcAkE oleHAM - - he is so nutty if he ate a can of Planters cashews - he could be charged with CANNIBALISM ....


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80fbody
mopar


Reged: Oct 25 2006
Loc: Mass.
Re: 727 - Air Check - Not Going Well? [Re: MisterFiberglass]
      #7862123 - Sun Sep 22 2013 08:10 PM

I just cleaned all the vasaline type assembly lube off the lip seals & re-assembled. Now that I've also learned I can install only the front clutch on the pump & air-check it's so much easier to see what's going on. Definitely better this time.

Going to get all new lips seals tomorrow & only use ATF on them this time. I think it may just give a better feel on the air-check.


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dvw
master


Reged: Mar 16 2006
Loc: MI, usa
Re: 727 - Air Check - Not Going Well? [Re: 80fbody]
      #7862220 - Sun Sep 22 2013 08:58 PM

There are only 2 points of leakage when air checking with the pump. The seals on the piston and the large diameter rings on the reaction shaft (back side of the pump) that seal the pump to the drum. Are there grooves inside of the drum where they ride? If the drum is worn, they're cheap. I just bought a new Dorman drum at my supplier Thursday for $32. That being said the front clutch is always lazier during air testing than the rear drum. And yes it's easier to air check with the pump rather than assembling the unit.
Doug


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80fbody
mopar


Reged: Oct 25 2006
Loc: Mass.
Re: 727 - Air Check - Not Going Well? [Re: dvw]
      #7862279 - Sun Sep 22 2013 09:28 PM

You know, that's it. It's lazyier than the rear clutch. That sums it up. Guess I really don't have an issue. Not knowing how it "should" act is my biggest problem. The drum isn't grooved & the rings fit nice. With new lip seals, I'm going to run it.

Thanks, that really eases my mind.


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jamesc
master


Reged: Jan 20 2003
Loc: communist bloc of new jersey
Re: 727 - Air Check - Not Going Well? [Re: dvw]
      #7862359 - Sun Sep 22 2013 10:23 PM

Quote:

I just bought a new Dorman drum at my supplier Thursday for $32.




can you elaborate on that?

--------------------
1.17 60' 8.21 @ 162
ehead 451

"Power wears out those who don't have it"



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