Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > Porsche 911 Technical Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Oct 2010
Posts: 124
Garage
PMO manifold brake booster check valve.

The check valve that came with my PMO carburetors for the brake booster hose connection is made out of plastic. It gets brittle from the engine compartment heat and breaks.

I'm trying to find a brass version of this same fitting.
I think the size is 3/8".
Its threaded on one end to attach to manifold and and has barbed hose connection on the other end to attach to power brake booster hose.

Does anyone know where to find a replacement for this fitting?
Preferably brass, but I'd take the plastic one if that's all I can get.
Old 07-16-2017, 03:40 PM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Registered User
 
Join Date: Jan 2007
Posts: 1,925
I just ran a barbed brass hose fitting at the intake manifold and used a metal datsun check valve that had a hose fitting on either side that I already had and it worked out fine.
Old 07-16-2017, 04:00 PM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Oct 2010
Posts: 124
Garage
Any idea what size fitting it takes on the barbed end and the threaded end?
Old 07-16-2017, 04:42 PM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Jan 2007
Posts: 1,925
The PMO fitting if I remember correctly is more like a 1/2" thread and a around that size at the hose area as well.
Old 07-16-2017, 05:01 PM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
porscheboy1
 
Join Date: Aug 2010
Location: Cayce, SC
Posts: 97
Garage
Question Brake booster check valve

Does this check valve have to be used? My brake booster line is attached directly to the manifold with out it and everything seems to work fine.
Old 07-17-2017, 05:55 AM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Jan 2007
Posts: 1,925
I do believe that you DO need a check valve.
Old 07-17-2017, 07:44 AM
  Pelican Parts Technical Article Directory    Reply With Quote #6 (permalink)
Registered User
 
Join Date: Oct 2010
Posts: 124
Garage
I was told the check valve keeps backfires from blowing out the power booster diaphragm.
__________________
---------------------------------------------------------
83 911 SC, 3.2L bore, 964 cams, 46mm PMO carbs.
Old 07-17-2017, 01:45 PM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)
Registered User
 
Join Date: Jun 2009
Location: St Paul MN
Posts: 1,751
Garage
Just tossing this out, but could you put a hose at the carb and run the valve off to the side away form the really hot parts and then up to the booster?
__________________
Rutager West

1977 911S Targa Chocolate Brown
Old 07-17-2017, 03:02 PM
  Pelican Parts Technical Article Directory    Reply With Quote #8 (permalink)
Registered User
 
Join Date: Oct 2010
Posts: 124
Garage
I contacted PMO, and Richard shipped me a new one. Waiting for it to get here.
In the meantime I JB welded the broken one back together, made sure the check valve was still working, put it back on the car and its working fine.

I think ultimately, if I can find the a brass fitting for the manifold, I'll pick up an inline barbed connector check valve and move it as far back in the engine compartment as possible.

Having trouble locating the fitting at the moment though.
__________________
---------------------------------------------------------
83 911 SC, 3.2L bore, 964 cams, 46mm PMO carbs.
Old 07-17-2017, 03:33 PM
  Pelican Parts Technical Article Directory    Reply With Quote #9 (permalink)
Registered User
 
Join Date: Jan 2007
Posts: 1,925
Yes rwest. That is what I did.
Old 07-17-2017, 03:53 PM
  Pelican Parts Technical Article Directory    Reply With Quote #10 (permalink)
porscheboy1
 
Join Date: Aug 2010
Location: Cayce, SC
Posts: 97
Garage
hdrockerroller. Thanks for the info that a backfire can destroy the diaphragm in the power brake unit. I'll find my check valve and install it away from the heat.

Regards,

John
Old 07-17-2017, 05:57 PM
  Pelican Parts Technical Article Directory    Reply With Quote #11 (permalink)
Registered User
 
Join Date: Oct 2010
Posts: 124
Garage
I received the new check valve from PMO.
They have changed their setup to use an elbow that screws into the manifold and a plastic check valve that you can put anywhere in line between the manifold and power brake booster.

This is similar to zedsn's solution, except that the PMO parts are all plastic.
__________________
---------------------------------------------------------
83 911 SC, 3.2L bore, 964 cams, 46mm PMO carbs.
Old 07-19-2017, 02:01 PM
  Pelican Parts Technical Article Directory    Reply With Quote #12 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
Tidybuoy's Avatar
 
Join Date: Jun 2003
Location: Fresno, CA
Posts: 5,912
Garage
I don't have a check valve because my '74 does not have the brake booster.

However, does the check valve have to be right at the manifold? Why not connect to the intake manifold and put the check valve up front where you don't have the engine heat?
__________________
Vern

'74 911 Coupe - Silber Metalic (963-93), PMO ITB Injection and Electromotive Management
'88 944 Coupe - Nougat Brown Metalic
'74 914 Targa - Light Gray 2.0
Old 07-19-2017, 02:21 PM
  Pelican Parts Technical Article Directory    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Oct 2010
Posts: 124
Garage
Tidybuoy:
The only argument I can think of for keeping the check valve closer to the manifold is to keep the pressure from backfires from traveling up the power brake booster line.
__________________
---------------------------------------------------------
83 911 SC, 3.2L bore, 964 cams, 46mm PMO carbs.
Old 07-19-2017, 03:13 PM
  Pelican Parts Technical Article Directory    Reply With Quote #14 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 

Tags
check valve , fitting , pmo


All times are GMT -8. The time now is 02:35 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2016 Pelican Parts - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.