Hard brake pedal

[IDIBRONCO]

and 60 miles north of us. When
up there I pick up things.
It`s a Candy store of goodies.

I'd go broke in a hurry!

With the engine off the vac dropped from 22 inHg to ~20 over ~hour. Is it supposed to hold vac?

I supposed that it is supposed to, ideally. As old as our trucks are, yours HAS to be in the top .001% at holding vacuum. All of the old rubber parts most likely can't hold a perfect vacuum. With the vacuum pump that I still carry for emergencies, mine would drop to 0 in about 5 minutes after shutting off the engine. After I replaced it, it would take 10-15 minutes. I never did see more than 16.5" of vacuum out of that old pump so it wasn't the best even when new. Now, with the two after that, I get 22"-23" while driving so I'm happy with that.

 

[tradergem]

My old vacuum pump would have good vacuum when I first started the truck but would quit working after driving for a while. The vacuum pump I replaced that one with four years ago just got weaker and weaker on vacuum before being replaced. Apparantly they have more than one way to fail.

 

[Cubey]

My old vacuum pump would have good vacuum when I first started the truck but would quit working after driving for a while. The vacuum pump I replaced that one with four years ago just got weaker and weaker on vacuum before being replaced. Apparantly they have more than one way to fail.

Including falling apart.

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[IDIBRONCO]

That's right. This is mine from last fall.

 

[Old Goat]

PNP Auto Parts has worked for me. Think I have 4 good one`s,
life time guarantee, as long as Iam still alive and able to pull them.


Goat

 

[Cubey]

PNP Auto Parts has worked for me. Think I have 4 good one`s,
life time guarantee, as long as Iam still alive and able to pull them.


Goat

I still have the used spare from @BlindAmbition with the bracket and pulley. I had to use it on the RV twice when two new pumps failed. First just quit pumping and the other fell apart. My lifetime pump is from O'Reilly's. I made sure to keep both when I got the van. The pump that came on the van was put onto the RV before it was sold. So the van is running the lifetime pump with the good spare under the passenger seat. And I carry around the pulley puller tool, too.

 

[rreegg]

all the original symptoms persist: pedal starts out “normal” in the morning and gradually gets more firm, firm pedal after sitting overnight.

I’m now looking into rear brake adjustments and master cylinder/booster pushrod adjustments.

The brakes have always been much better on the second push. The first push on the pedal will get pretty deep and then the second will firm up maybe half way down, with good braking action.

Is this an indication the rear drums or pushrod should be adjusted?
Adjusted the rears about a month ago and they can spin about a full 360* turn after stopping on their own - can hear shoe contact.

Have never adjusted the pushrod when replacing the booster so that may be something to do - make it like 1/4” longer

I’ve always thought the above behavior was due to incomplete bled brake lines but they should be bled

 

[IDIBRONCO]

Have never adjusted the pushrod when replacing the booster so that may be something to do - make it like 1/4” longer

I don't have a lot of advice here except to watch out when you adjust the pushrod. If you extend it too far, then it will keep enough pressure on the master that the brakes won't fully release. Eventually, they will get hot from dragging. Eventually, they'll start smoking since the hot fluid will expand, pitting even more pressure on the master. That's been my experience. From what I remember, you should adjust the pushrod on the new booster to extend out as far as the one did on the old booster.

 

[Cubey]

Making the push rod longer would probably make it worse.

 

[rreegg]

Making the push rod longer would probably make it worse.

Yeah, you're not wrong. Kind of grasping at straws here to figure what else can be done or tweaked. Obviously the vac pump is a high failure part but I've no vac numbers to suggest that's the problem here. I've elongated the booster pushrod by 4 quarter turns so far and will see how it does.
May end up replacing rear shoes and hardware, though they seem to be in decent shape. The edges of the shoes, that grab on the parking brake lever, are a bit bent up so it would probably help the parking brake catch better at the very least.

 

[IDIBRONCO]

I've elongated the booster pushrod by 4 quarter turns so far and will see how it does.

Cubey's probably right. If that make sit worse, then you'll have to go the other way and make the rod shorter.

 

[Old Goat]

There is a tool to make the Booster Rod adjustment, Here is a good video
explaining how to use the tool.

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Here is a little Google search I did,

Master cylinder/booster rod adjustment tool - Google Search

Goat

 

[rreegg]

Thanks Goat very helpful.

Did a test where you apply the parking brake halfway and see how that adjusts the brake pedal feel. That made the brakes feel better. Am likely gonna replace rear shoes and hardware. Went down to adjust rear brakes and couldn’t get the driver side shoes to rub on the drum at all. Passenger side is good.

Also rotated tires and verified rear shoes are 3”

 

[rreegg]

Come to think of it I’m not positive the wheel cylinders I put in are the 3” variety. It’s possible one or both are 2.5” since replaced them separately.
Pricing out brake components last night and rock auto is quite a good site, their variety is unmatched and have a wide range of price points. I like brick n mortar but not sure how much I like it $$ wise

 

[Cubey]

I like brick n mortar but not sure how much I like it $$ wise

They're good for lifetime warranty parts, or needing something in a hurry when out on a long trip, where you cannot easily get packages. Otherwise? They sell the same stuff as RockAuto.