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line pressure adjustment

Posted By: rebel

line pressure adjustment - 12/11/10 10:37 AM

how many psi increase will i get if i adjusted my line pressure 1 complete turn? since you have to drain the fluid & pull the pan i don't want to be doing multiple trips into transland, so if i get a few answers, logic dictates i choose the average. it's a A&A Ultimate low band brake with the clean N at the end of the shifter in a 727. thanx for your input.
Posted By: 440Jim

Re: line pressure adjustment - 12/11/10 02:26 PM

Some valve body manufacturers use different springs in the regulator. So I would call A&A and ask them for that exact valve body. I only have the info for the Griner manual (footbrake) valve body that I use.

What pressure is it at now?
FWIW, I am at 165 psi.
Posted By: rebel

Re: line pressure adjustment - 12/11/10 06:39 PM

i'm a little over 100 psi & 165 is where i'm aiming for. my problem is, i'm going racing today & want to wind up the pressure before i go racing.
Posted By: John_Kunkel

Re: line pressure adjustment - 12/12/10 12:17 AM

You won't gain 65 psi with a simple adjustment.
Posted By: Anonymous

Re: line pressure adjustment - 12/12/10 01:17 AM

Quote:

You won't gain 65 psi with a simple adjustment.




Posted By: 440Jim

Re: line pressure adjustment - 12/12/10 01:39 AM

Quote:

i'm a little over 100 psi & 165 is where i'm aiming for. my problem is, i'm going racing today & want to wind up the pressure before i go racing.

I believe that will require a regulator spring change.
I am surprised that trans brake has such a "low" pressure. I would have guessed it would be 120-140 minimum.
Posted By: rebel

Re: line pressure adjustment - 12/12/10 10:19 AM

well for what it's worth. 2 complete turns gained 50 psi. no springs required.
Posted By: 440Jim

Re: line pressure adjustment - 12/12/10 02:22 PM

Quote:

well for what it's worth. 2 complete turns gained 50 psi. no springs required.

Wow, that is one wicked spring rate. For comparison, my Griner valve body instructions say 8 psi per turn.

Are you sure the original measurement was accurate (rpm, etc)? If it was 135 originally (the range I expected) and two turns gave you 150 that would be closer to the spring Griner uses. But I don't know about the A&A.
Posted By: rebel

Re: line pressure adjustment - 12/12/10 06:51 PM

the original test was done twice just to confirm it was only 100 as i was thinking i'm not measuring this correctly, but i was. so 2 turns later we were checking the SAME guage reading 50 psi higher in 1st gear like we checked before. i wasn't expecting such a big gain from 2 turns but then i've never done this test before.
Posted By: 65dragnet

Re: line pressure adjustment - 12/12/10 10:13 PM

Do yourself a favor , the next time you have your tranny out ,drill and tap the case in-line with the adjuster and put a plug in it. You can adjust the pressure without pan removal.
Posted By: John_Kunkel

Re: line pressure adjustment - 12/12/10 10:44 PM

Quote:

Wow, that is one wicked spring rate.



That's what I'm thinkin'. Two turns is a little over .080".
Posted By: rebel

Re: line pressure adjustment - 12/13/10 04:55 AM

Quote:

Do yourself a favor , the next time you have your tranny out ,drill and tap the case in-line with the adjuster and put a plug in it. You can adjust the pressure without pan removal.


yep, i was thinking that same thing when i was adjusting it. if i had an 1/8" tap & suitable drill i would have done it right there & then. it's a bit of a no brainer really but then how often would you adjust it?
Posted By: MR_P_BODY

Re: line pressure adjustment - 12/13/10 05:47 AM

Drilling and tapping would be a smart move on my part,
I'll be pulling a 518 apart in the next week or so
and I will probably need to adjust it... thanks for
the tip guys
Posted By: 440Jim

Re: line pressure adjustment - 12/13/10 05:39 PM

Raff,
This might help. This is how I did it.
The "mill 3/8 deep" is from the outer edge where the stampings are located. The case isn't that thick!

Attached picture 6355120-Line_Pressure_Adj_Access.jpg
Posted By: 440Jim

Re: line pressure adjustment - 12/13/10 05:43 PM

And the inside ends up looking like this:

Attached picture 6355128-Line_pressure_access_inside.jpg
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