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Jumper Valve Install
01/08/03
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About the Jumper Valve:

Some Turbo Buicks don't have the best brake holding power for hard launches at the drag strip. Some people blame the powermaster setup, some don't. The jumper valve works similar to a line lock, except in reverse. A line lock is open all the time, whereas a jumper valve is closed. When closed, your brakes work as normal. All brake pressure is sent from the master cylinder to the factory combination valve (located on drivers side frame rail) and them equally to the front and rear brakes. When the jumper valve is opened, a path is created around the combination valve so that almost all brake pressure goes to the rear brakes only. This gives you the extra holding power on the line for high boost launches.

My car didn't have the best brake holding power. I had the S10 wheel cylinders, the large rear shoes, and the drums where freshly cut. Even with all that done I could only hold about 5psi boost on the line before the rear wheels would start turning. After I installed a jumper valve, I have seen 15+psi boost several times. There was no sign whatsoever of the car moving either.

 

Parts Needed

Parts Needed:
(available from Graingers or other industrial supply distributors)

IMPORTANT NOTE: Part numbers may have changed since I bought them. Be sure to verify part numbers and inlet/outlet line sizing before final purchase.


Solenoid Valve
Quantity: 1

Description:Threaded Cartridge Solenoid Valve, Maximum Flow 5 Gallons per Minute, Maximum Pressure 3000 PSI, Valve Cavity C09-2, 2 Ways, 2 Positions, Normally Closed, 12 VDC
Manufacturer: PARKER
Mfg. Model#: DS091CD012LP
Grainger Item#: 4ZC98
Your Price: $54.05


Base
Quantity: 1

Description: Base, Female NPT Port 3/8 Inch, Port 1 Function Outlet, Port 2 Function Inlet, Fits Valve Number 4ZC98, 4ZC99, 4ZD51, 4ZD52, 4ZD53, 4ZD54, Height 1 3/4 Inches, Length 1 Inch, Width 1 3/4 Inches, Aluminum, Two Ports, For Threaded Cartridge Valve
Manufacturer: PARKER
Mfg. Model#: B0926P
Grainger Item#: 4ZC92
Your Price: $22.55


Brass Flare Fitting Union Tee
Quantity: 2

Description: Flare Fitting Brass, Union Tee, Tube Size 1/4 Inch
Manufacturer: PARKER
Mfg. Model#: 144F-4
Grainger Item#: 2P163
Your Price: $21.43 (for 10)


Brass Flare Fitting Nut
Quantity: 6

Description: Flare Fitting Brass ,Long Nut, Tube Size 1/4 Inch, Package 10
Manufacturer: PARKER
Mfg. Model#: 41FL-4
Grainger Item#: 2P143
Your Price: $6.16 (for 10)

 

Other Misc. Parts:

  • Length of 1/4" brake line (probably 4').
  • Length of 18 gauge wire (for switch).
  • Wire connectors (for switch, fuse panel, & solenoid attachment).
  • Brake fluid (need to bleed entire brake system).

 

Tools Needed:
  • Tubing cutter (for cutting brake line)
  • Tubing bender (that will fit the brake line you are using)
  • Double flare tool (available at almost any auto parts store)
  • Misc. wrenches to tighten fittings.
  • Wire striper and crimper (for switch and wiring).
  • Mity Vac or similar brake bleeding tool **optional**

 

 

Instructions:
IMPORTANT:
• It is suggested that you use SAE approved DOUBLE FLARE fittings for this job. In the pictures below you will see compression fittings, HOWEVER, I have since changed them all to double flared fittings like shown above.
• I DO NOT recommend that you install your jumper valve in the same location that I did. If I had to do it again, I would place it on top of the frame rail under the driver's side seat. See #5 below for more info.

As much as I'd like to write detailed instructions for this project, I'm not. I just don't have the time. Besides, I think the pictures are pretty self explanatory. Instead, I will write a few key items that you definitely should be aware of before and during this project. Here goes...

  1. When flaring your brake lines DON'T FORGET TO PLACE THE FLARED NUTS ON THE LINE BEFORE FLARING!
  2. Always cut your lines long. They can always be shortened after the fact. If you don't, you'll end up using a LOT of brake line.
  3. Take your time flaring the lines or else you'll end up with a bent line (possibly weakened) or a flare that isn't round and may leak.
  4. If you haven't flared or bent brake lines before, be prepared for a lot of swearing. This job is a complete pain in the... you know what. However, I think the end result is worth it.
  5. VERY IMPORTANT NOTE: This job would go a lot quicker if you place the jumper valve between the frame rail under the drivers seat, NOT where I placed it in the pictures (under the master cylinder). I did mine with the engine out of the car and it was still a total pain. Put it between the frame rail and make sure you secure it and bend the lines so that they are out of harms way.
  6. When bleeding the brake lines, a tool such as a Mity Vac is VERY useful. Pay CLOSE ATTENTION to the fluid reservoir. If it goes dry you'll have to start all over! I did it twice and it was a total pain in the a##!
  7. If you don't have it already, now would be a good time to replace the factory combination valve with the updated brass version (available from GM).

 

Photos:
IMPORTANT:
• It is suggested that you use SAE approved DOUBLE FLARE fittings for this job. In the pictures below you will see compression fittings, HOWEVER, I have since changed them all to double flared fittings like shown above.
• I also DO NOT recommend that you install your jumper valve in the same location that I did. If I had to do it again, I would place it on top of the frame rail under the driver's side seat. See #5 above for more info.

 


view image

Jumper valve & lines
Here you are looking at a side view of the jumper valve. You can see the rear brake line coming down from the master cylinder. Notice where the first of the two t-fittings is installed, and also how the valve is placed in relation to the body, frame, and other lines. The line exiting the valve is hard to see, but I point it out in the photo. All of the lines were VERY hard to flare (double flare - see tools above)... maybe because they are made of stainless steel?

Note: The wiring for the solenoid has not been run in this picture. It's very simple though. I have a ground going up towards the solenoids mounted on the front fender, and a power wire going to the switch, and then on to the fuse box. (see "Parts" section above for more info).

 

view image

Combination valve & lines
Here you can see the rest of the plumbing and where I tapped into the lines for the second t-fitting. This section was a lot easier to bend than the top, but overall was more difficult because I had to cut and flare the tubing while it was on the car (line runs all the way back to the rear axle).

 

For additional information or to post questions, go to sites such as gnttype.org, turbobuick.com, and turbobuicks.com.

That's all I've got. Good luck!!