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GM Disc/Drum Proportioning Valve for 3/8-24 Outlets

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Specs
Centerline of Holes:
2.69
Material Type:
Brass
Overall Height:
2.00
Overall Width:
1.08
Overall Length:
5.13
Sold in Quantity:
Kit
Finish:
Natural
Outlet Fitting:
Bottom front/Top front are 3/8"-24 IFF (to font brakes), Rearmost port is 9/16"-18 IFF (to rear brakes).
Garage Sale:
No
Notes
Includes hard lines with fittings, hardware, bracket, and brake light switch. This is a combo valve (metering for front/proportioning for rear) into one valve. Residual valves NOT built in.
GM Disc/Drum Proportioning Valve for 3/8-24 Outlets
Product Video
GM Disc/Drum Proportioning Valve for 3/8-24 Outlets

Click image to enlarge

Watch the video below to learn more about the differences in brake lines, flare types and fittings you may want to consider before plumbing away on your current chassis project.

Details

Reviews

Q & A

What's in the Box

These proportioning valves are similar to what GM used on many cars in the 70's. They are non-adjustable and may require an adjustable valve in the rear brakes (if needed). Block incorporates metering (for front brakes) and proportioning (for rear brakes) into one unit. For use with front disc, rear drum brake systems.

Includes hard lines to connect to a master cylinder with 3/8"-24 outlets.

910-31364 Instructions (PDF)

Notes

Bottom Front Port: 3/8"-24 IFF threads - goes to one front brake
Top Front Port: 3/8"-24 IFF threads - goes to one front brake
Middle Top Port: 1/2"-20 IFF threads - comes from master cylinder
Rear Top Port: 7/16"-24 IFF threads - comes from the master cylinder
Rear Most Port: 9/16"-18 IFF threads - goes to rear brakes

Item Details

For M/C with 3/8"-24 outlets.

Customer Reviews

Rated 5 out of 5 by 3 reviewers.
RATING BREAKDOWN
3 reviews
5 Stars
3
4 Stars
0
3 Stars
0
2 Stars
0
1 Star
0
RECOMMEND THIS PRODUCT:

Blt 2 Run
Verified Purchaser
West Palm Beach, Fl
Product Rating

Solved my problem

August 02, 2012
I needed to install it on the opposite side of the master cyl. and had to bend the bracket and one line in the other direction, an option of where it will be mounted would give the customer a choice of hardware. Thanks Jack
Yes, I recommend this product.
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kaputafj
Verified Purchaser
Product Rating

76 GMC 1/2 ton

November 01, 2014
quick shipment, works just fine. installed easily.
Yes, I recommend this product.
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Dway
Verified Purchaser
British Columbia, Canada
Product Rating

This product was well machined and mount

May 14, 2014
The product was delivered on time and was as described in the catalog. The installation well quickly with the valve body mounting right into the original OEM location and required no modification to existing brake lines. Good product
Yes, I recommend this product.
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Page 1 of 1
91031364

Product Q&A

5 questions : 6 answers

2 answers

What brake line line size is supported on the rear brake port? Thank you for the information for M/C and front brake line size. What rear brake line size is supported? PDF diagram does not show brake line size, only tube nut size.

jcostan
March 28, 2014

What brake line line size is supported on the rear brake port? Thank you for the information for M/C and front brake line size. What rear brake line size is supported? PDF diagram does not show brake line size, only tube nut size.

Answers

May 15, 2014
Dway
The rear brake port is 1/2 in requiring a 9/16 wrench
March 31, 2014
EricM
The original GM applications used 1/4" line to the rear brakes. If you would like to use a 3/16" brake line to connect to the rear brake port of this proportioning valve then you will need adapter part number 9103183-9/16.
1 answers

what brake line size is supported? Are all ports on this product for 3/16 brake tube size? I understand the difference in the tube nut sizes, but I need to confirm a 3/16" inverted flair line will fit in the front and rear ports to the MC, front line brake ports and rear brake port.

jcostan
March 27, 2014

what brake line size is supported? Are all ports on this product for 3/16 brake tube size? I understand the difference in the tube nut sizes, but I need to confirm a 3/16" inverted flair line will fit in the front and rear ports to the MC, front line brake ports and rear brake port.

Answers

March 28, 2014
EricM
The small end of the lines from the valve to the master cylinder are for the 3/16 line with the thread nuts in 3/8 x 24. The opposite end of the lines connect to the valve with the ½ x 20 to the front brakes and 7/16 x 24 for the rear. There are two outlets on the valve for the front brakes and exiting the valve in 3/8x24 which is the standard fir 3/16” line. The outlet for the rear brakes is 9/16x18 and if you want use 3/16 line adapter 9103183-9/16 will be needed. A photo of the valve with fitting sizes labeled is shown in the instructions here: http://static.speedwaymotors.com/pdf/910-31351%20MBM%20prop%20valve.pdf
1 answers

What proportioning valve do I have? I am trying to figure out the brake system on the car I got and I'm wondering if I have a disk disk proportioning valve on a disk Drum car. The number on the back of the proportioning valve is hj 8 087 9419. Any idea what this is?

Capedbandit
Az
March 12, 2014

What proportioning valve do I have? I am trying to figure out the brake system on the car I got and I'm wondering if I have a disk disk proportioning valve on a disk Drum car. The number on the back of the proportioning valve is hj 8 087 9419. Any idea what this is?

Answers

March 13, 2014
EricM
We apologize but the number you referenced does not match any of our suppliers numbers and is likely to be a batch or run number. If it has a brand on it you may try the nearest supplier for that particular brand for possible cross over on his computer system. If you have a disc/disc valve on a drum brake car the rear wheels will have a tendency to lock up prematurely especially on hard or emergency braking.
1 answers

I bought a brake booster combo, part #91031409, and installed on a "95 S-10 frame with disc front, drum rear. Is this proportioning valve compatible? Rat Rod

Marvin
Forest Lake, MN, USA
October 01, 2013

I bought a brake booster combo, part #91031409, and installed on a "95 S-10 frame with disc front, drum rear. Is this proportioning valve compatible? Rat Rod

Answers

October 01, 2013
Jason
This proportioning valve is intended for vehicles having front DISC brakes and rear DRUM brakes. It includes hardlines that connect the proportioning valve to a master cylinder that has 3/8" outlets. This is a 'combination' valve. It incorporates metering (for the front brakes) and proportioning (for the rear brakes)into one valve. This valve does *NOT* contain built in residual valves.
1 answers

where is the 3/8 outlet on this is it for the rear brakes?

scott
ca
August 23, 2011

where is the 3/8 outlet on this is it for the rear brakes?

Answers

August 23, 2011
Jason
"This valve is intended for vehicles having front DISC brakes and rear DRUM brakes. It includes hardlines that connect the proportioning valve to a master cylinder that has 3/8" outlets." ************************************** This is a 'combination' valve. It incorporates metering (for the front brakes) and proportioning (for the rear brakes)into one valve. This valve does *NOT* contain built in residual valves. ADDIT INFO: THE BOTTOM FRONT PORT HAS 3/8"-24 IFF THREADS AND GOES TO ONE FRONT BRAKE. THE TOP FRONT PORT HAS 3/8"-24 IFF THREADS AND GOES TO ONE FRONT BRAKE. THE MIDDLE TOP PORT HAS 1/2"-20 IFF THREADS AND COMES FROM THE MASTER CYLINDER. THE REAR TOP PORT HAS 7/16"-24 IFF THREADS AND COMES FROM THE MASTER
Page 1 of 1

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This adjustable proportioning block allows you to run lines from the master cylinder to the block and then to the appropriate wheels. What is neat about it is that it also contains the proportioning valve and brake light switch. This dramatically reduces the amount of fittings needed and potential leaks.

The adjustable proportioning valve regulates rear brake pressure, helping to maintain correct brake bias between front and rear brakes. It is designed for dual bowl master cylinders. The distribution block connects to the master cylinder and distributes brake fluid to all four wheels. An easy to turn handle with directional arrows makes it simple to either increase or decrease rear brake pressure.

The block accepts 3/16" brake lines and the inlets and outlets on this unit are 3/8"-24 inverted flare females.  It has two inlets from the master cylinder, two outlets to the front brakes and one outlet to the rear brakes.  It includes five stainless steel 3/16" fittings and wiring pigtail for rear brake light switch. Mounts to any convenient location. This is not a direct factory replacement for original blocks. Some line modifications may be necessary.

910-31358 Instructions (PDF)

Learn more about how adjustable proportioning valves work by reading our tech article. Brake System Selection.  

GM Disc/Drum Proportioning Valve for 1/2-20, 9/16-18 Outlets
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These proportioning valves are similar to what GM used on many cars in the 70's. They are non-adjustable and may require an adjustable valve in the rear brakes (if needed). Block incorporates metering (for front brakes) and proportioning (for rear brakes) into one unit. For use with front disc, rear drum brake systems.

Includes hard lines to connect to a master cylinder with 1/2"-20 and 9/16"-18 outlets.

GM Proportioning Valve Plumbing Instructions (PDF)

Wilwood 260-11179 Adjustable Proportioning Block
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This block has the proportioning valve built-in to the rear brake ports and a stop light switch built into the front brake ports. All ports are 3/8"-24 inverted flare female.

  • Compact design simplifies mounting, plumbing, & wiring
  • Maintains full isolation between front and rear fluid circuits
  • Rear circuit has a single inlet and single outlet with the adjustable proportioning valve
  • Front circuit has a single inlet with two outlets

Proportioning Valve Installation Instructions (PDF)

Brake System Builder's Tip (Link)

Detailed Schematic of Proportioning Block 

Learn more about how adjustable proportioning valves work by reading our tech article. Brake System Selection.   

9/16-18 IFM to 3/8-24 IFF Adapter
(Part #9103183-9/16)
                        

Brass adapters. Select from:

  • 3/8"-24 IFM to 7/16" - 24 IFF
  • 7/16"-24 IFM to 3/8" - 24 IFF
  • 1/2"-20 IFM to 3/8" - 24 IFF
  • 9/16"-18 IFM to 3/8" - 24 IFF