Hard to brake - brake booster bad?

[RangerX]

I'm looking at an 89 Ranger that’s for sale, for a friend. It’s 2wd, 2.9 engine, auto trans.
I’m thinking the brake booster may be bad, because there is pretty much no power assist to the brakes.
I did not even pop the hood to look at it yet, I’ll look when I go back tomorrow in the daylight.
I’m a little unsure on the operation of the booster. My Ranger had a 1/4” hole rusted thru its booster, it caused a high idle but brakes were still working well. So I’m not sure what’s inside one.p, and how it actually operates.
Is there something else to cause no power to the brakes? I really had to almost stand on them to come to a stop when I did a quick test drive.

 

[BrooklynBay]

Check the rubber grommet, the check valve, and the hose.

 

[Stic-o]

Maybe somebody did a bad job bleeding the brakes, and is trying to dump it because they can't figure it out.

 

[410Fortune]

Could need a master cylinder or have air in the lines even without a "booster" you should still be able to stop
A vacuum booster is pretty easy to check, first is there any signs of fluid leaking down between the master and booster?
Does the booster hold vacuum? after you shut the engine off and you move the grommet/vacuum line is there vacuum inside the booster?


Think about it like this the big round booster is basically a big rubber valve, with engine vacuum being applied to the back side. When you depress the master cylinder plunger the big rubber diaphram is being pulled in by engine vacuum which multiplies your foot pressure, or "boosts/multiplies" the amount of force you apply

Even without the engine running the master cylinder and your foot should still be capable of making enough hydraulic pressure to squeeze the calipers and push out the rear wheel cylinder to activate the brakes pads and shoes.
More likely air in the lines, bad seals in the master, worn out calipers/ wheel cylinders (rear drums) or soft rubber brake lines.
Any combination of these can cause soft brakes that you have to "stand on" to get to stop.
Not a fun feeling

It is pretty common for a 80's ranger to need brake work/upgrades.
The 91-94 explorer booster and 95+ master yclinder is a big upgrade for those old trucks. I have a 94 booster and 95 master in my 88 running 97 ranger front discs (dual piston calipers in 96/97 ttb) and 97 explorer rear discs, the truck stops better then anything else we own...even with 35's

 

[RangerX]

Thanks guys.
The guy selling it is an older guy that I’ve met before, lives in town, seems pretty honest, and he told me all he’s done to the brakes, new shoes and pads, bleeding etc. He and his wife have been driving it like this.
I’ll look at the grommet and hose today, see if it’s just that.
It just shocked me a little when I went to drive it, put my foot on the brake and shifted into drive, and the the truck started to drive away! Had to really press hard to keep it stopped until I actually wanted to go. Hard pedal, not spongey.

 

[RangerX]

Could need a master cylinder or have air in the lines even without a "booster" you should still be able to stop
A vacuum booster is pretty easy to check, first is there any signs of fluid leaking down between the master and booster?
Does the booster hold vacuum? after you shut the engine off and you move the grommet/vacuum line is there vacuum inside the booster?


Think about it like this the big round booster is basically a big rubber valve, with engine vacuum being applied to the back side. When you depress the master cylinder plunger the big rubber diaphram is being pulled in by engine vacuum which multiplies your foot pressure, or "boosts/multiplies" the amount of force you apply

Even without the engine running the master cylinder and your foot should still be capable of making enough hydraulic pressure to squeeze the calipers and push out the rear wheel cylinder to activate the brakes pads and shoes.
More likely air in the lines, bad seals in the master, worn out calipers/ wheel cylinders (rear drums) or soft rubber brake lines.
Any combination of these can cause soft brakes that you have to "stand on" to get to stop.
Not a fun feeling

It is pretty common for a 80's ranger to need brake work/upgrades.
The 91-94 explorer booster and 95+ master yclinder is a big upgrade for those old trucks. I have a 94 booster and 95 master in my 88 running 97 ranger front discs (dual piston calipers in 96/97 ttb) and 97 explorer rear discs, the truck stops better then anything else we own...even with 35's

She ended up buying it today, $400. I’m the king at finding cheap cheap Rangers.
I did a quick look at the booster, but didn’t do any tests that you described. Maybe I can in the next few days. But it does have a brand new master. It also idles high, so that may mean a vacuum leak in the booster.
She drove it around and didn’t think it was that big of a deal, so...
When I drove it, it reminded me of my first car, a 54 Willys, that had manual brakes. But it’s been 40+ years since, and I was caught off guard by the lack of stopping power in this truck!
Oreillys surprisingly has one in stock for that year, for $66. Or I could pull the one off my 95 Ranger? But for 66 bucks for new, it doesn’t seem worth pulling.

 

[410Fortune]

Congrats!

I prefer the 95 booster myself, its larger and gives you better brake BUT the $66 unit may also work, by 89 I think the ranger already had the larger booster......

I would buy up as many $400 rangers as I could...they are starting to make a comeback price wise