Part Choice-Brake System

[Scruffy49]

The round white plastic piece at the booster end of the hose is the valve. Follow the hose back from there and you'll see a black canister with a metal ring around it, thats the filter

Oh, I’ve seen it… Ralph is nearly stone stock, right down to the literally crumbling cast iron Qjet 85/86 -ONLY- 4.3L V6 intake manifold…

Can’t wait to 350 swap him, soooo much easier to find parts…

 

[Dejure]

School is still out, regarding the filters between the intake manifold and the power steering booster cans (said by someone who doesn't know anatomy from a hole in the ground, regarding these matters).

Searches indicate these are both filters and check valves. Though some of the information given is a head scratcher.

For example:

1.0 Since the hose runs between the pump and the intake manifold, we are talking about vacuum on the can, with the engine running.

1.1 It's indicated the whole purpose of the connection between the manifold and the can is, to boost power brake function by way of engine vacuum.

1.2 There is nothing passing through the hose but air from the power steering can, as a vacuum is applied.

1.3 Based on "1.2," above, there is nothing coming out of the can to be filtered (we hope?).

1.4 If the manifold puts a vacuum on the can [to assist function], shutting off the engine might leave a vacuum on it for a short while, when the engine is turned off, and until it bleeds off. This could case a reverse flow of air from the manifold, and which could be contaminated with gas fumes, and oil vapors getting past tired rings.

1.5 IF these incorporated a check valve, the aforementioned issues would be minimal.

1.6 It's indicated the filtering function of these is, to absorb gas vapors that could make it back to the can.

1.7 It's indicated these are directional (have an arrow showing which side goes to the can and which goes to the intake manifold), suggesting there is a one way/check valve to only allow air to flow one way.

1.8 Noting suggests it matters if the filter and/or check valve is in the vertical or horizontal position.

1.9 The above would suggest these last forever and a day, since they, generally, don't have to do much actual filtering.

 

[DoubleDingo]

I thought that was the 1 way valve… Factory issued in Ralph, so I guess 41 years is beyond its rated service life…

Same here. Wondered why it needed two check valves on that vacuum line. Now I know I need to replace it, pretty sure it's a factory unit.

 

[Terlingueno]

Searches indicate these are both filters and check valves. Though some of the information given is a head scratcher.

For example:

1.0 Since the hose runs between the pump and the intake manifold, we are talking about vacuum on the can, with the engine running.

1.1 It's indicated the whole purpose of the connection between the manifold and the can is, to boost power brake function by way of engine vacuum.

1.2 There is nothing passing through the hose but air from the power steering can, as a vacuum is applied.

1.3 Based on "1.2," above, there is nothing coming out of the can to be filtered (we hope?).

1.4 If the manifold puts a vacuum on the can [to assist function], shutting off the engine might leave a vacuum on it for a short while, when the engine is turned off, and until it bleeds off. This could case a reverse flow of air from the manifold, and which could be contaminated with gas fumes, and oil vapors getting past tired rings.

1.5 IF these incorporated a check valve, the aforementioned issues would be minimal.

1.6 It's indicated the filtering function of these is, to absorb gas vapors that could make it back to the can.

1.7 It's indicated these are directional (have an arrow showing which side goes to the can and which goes to the intake manifold), suggesting there is a one way/check valve to only allow air to flow one way.

1.8 Noting suggests it matters if the filter and/or check valve is in the vertical or horizontal position.

1.9 The above would suggest these last forever and a day, since they, generally, don't have to do much actual filtering.

Well...

1.2 Power steering pump?

1.3 Yes, since power brake system is not connected to power steering pump

1.5 Stated by the factory shop manual (1985 C/K 5.7L), it is a filter only. The check valve is on the front face of the booster body

1.7 There is no indication in the aforementioned factory shop manual that the filter is directional. Nor are there any arrows on the filter itself indicating a direction

1.8 The illustration in the factory shop manual shows the filter in the vertical position, with the 90 degree elbow pointing to the booster check valve. Also stated that the check valve nipple should be positioned 'from vertical' and the illustration shows the check valve nipple at 90 degrees from vertical toward the filter

 

[Dejure]

Hmmm. On that 1.5 thing. check valves are dirt simple.

I made one, as an experiment, using a 1" long, 3/4" nipple, two caps, a spring and a silicone ball. I ground the inside of one cap, drilled holes in both. . . . Not much to fail. As such, if an integral part of the can, it should last that forty or so years our rigs have come to know.

On the 1.7 thing, guess it would depend. Even many filters (gas, furnace filters, etc.) want us to install a certain way because of the way reinforcements are installed, to keep the filter media from miss-forming.

Then there's 1.8. Is it just that the filter was installed because if worked for them? Just as mufflers were installed a certain way, fuel filters, air filters and so on.

Schools still out, but if the replacements sold and that mount on a floppy hoses don't carry any asks with regard to horizontal vs vertical, it may not be important.

UNLESS the filters actually have build up in the interiors and, aside regularly driving up and down 45-degree angle hills, need to be able to work as reservoirs for storing filtered junk, until replaced.

 

[Steelbuddha]

It would seem I am still on something close to the original filter. Changing it every 42 years isn't too bad.

 

[Fat 454]

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OOH nice ! - is that factory original willow green on your rig? Any chance of a paint code, as that is what I'm wanting to paint mine. Cheers.

 

[Terlingueno]

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OOH nice ! - is that factory original willow green on your rig? Any chance of a paint code, as that is what I'm wanting to paint mine. Cheers.

The original paint color is United States Forest Service green. On the glovebox RPO tag it says 'Special Paints' WE7941. I painted the exterior with Krylon Flat Sand.

 

[Fat 454]

Cool - even better - I had wanted a forest service looking truck. I'll see if the local shop can match that code ( do you know if there is a paint brand associated with the code ? ) - Cheers

Something like this ..

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[Terlingueno]

Cool - even better - I had wanted a forest service looking truck. I'll see if the local shop can match that code ( do you know if there is a paint brand associated with the code ? ) - Cheers

Something like this ..

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Yeah, except the top on mine is green like the rest of the truck. I didn't choose it for the color, I chose it because of the SM465 4 speed, 4.10 gears, 4 wheel drive, 350 engine, 40 gallon gas tank, plus it only had 70,465 miles on it and the price was $5000 when I signed the papers in 1994.

 

[AuroraGirl]

I tried finding a photo of mine. Don't recall it being secured by a bracket, but now I'm curious

I think they usually have a hard pipe threaded into the CARB or tbi, so maybe no bracket

 

[DoubleDingo]

I think they usually have a hard pipe threaded into the CARB or tbi, so maybe no bracket

It is a 3/8 hard line from the carb