Hydro boost brake conversion

[jjdeneen918]

Sweeting called me back this evening.

He said it sounded like the thing overheated.

He would say which application the booster came from, but said they are all basically the same 2000+ model years.

He said to buy a universal rebuild kit. It was several different sizes of rubber seals to pick from.

 

[JoeCova]

I have no pedal & very poor braking.

The pedal goes to the firewall, no resistance or stopping.

Within the final inch of pedal, I can stand on the pedal & slowly come to a stop.

Is your steering the same or heavier?

Could also be your lower steering pump or have an air leak into the system.

 

[JoeCova]

Sweeting called me back this evening.

He said it sounded like the thing overheated.

He would say which application the booster came from, but said they are all basically the same 2000+ model years.

He said to buy a universal rebuild kit. It was several different sizes of rubber seals to pick from.

View attachment 4023943

Yup, all made by Bosch, differences are minor.

Are you using a dual return reservoir or the derale power steering cooler?

 

[White Stripe]

Sounds to me like a loss of pressure in a brake circuit. You sure no brake lines or hoses didn't burst or come loose? Are the brake hoses original 30 year old hoses?

 

[jjdeneen918]

Yup, all made by Bosch, differences are minor.

Are you using a dual return reservoir or the derale power steering cooler?

Yes, I’m using the Wits End Derale cooler kit.

 

[jjdeneen918]

Sounds to me like a loss of pressure in a brake circuit. You sure no brake lines or hoses didn't burst or come loose? Are the brake hoses original 30 year old hoses?

I checked every connection under the hood, at each wheel, & confirmed fluid in MC.

 

[White Stripe]

I checked every connection under the hood, at each wheel, & confirmed fluid in MC.

It could be a bad master cylinder too.

 

[jjdeneen918]

It could be a bad master cylinder too.

I hadn’t thought of that. Is there an easy way to check each system?

I’d hate to just start throwing parts at this thing.

 

[White Stripe]

I hadn’t thought of that. Is there an easy way to check each system?

I’d hate to just start throwing parts at this thing.

Pinch off one circuit and see if the pedal still goes to the floor. Try with each brake circuit individually. Will tell you if you have a bad piston seal. Youtube has videos on checking a bad brake master.

 

[jjdeneen918]

The shop got a tool from a local dealership to test the hydroboost for function.
I’m waiting to hear back from them shortly.

 

[jjdeneen918]

I was told by the shop today, after the hydrobooster was replaced, that the master cylinder was bad too.

$2000 later, all was fixed.

I’m now just a few miles down the freeway & the car started shaking real bad & a lot of pedal to stay at speed.

Pull over on the highway & backing plates burnt my fingers.
Front brakes are totally locked up (maybe all?).
Waiting on a tow truck to bring us back to the closed shop.

Another hotel room & another day wasted.

More of a rant than anything. Super pissed that 2 days & $2000 later I’m still stranded.

 

[White Stripe]

Ive never seen a hydroboost go bad. Ive seen them leak a bit at higher mileage, but all that does is you have to top up the power steering fluid here n there.

 

[JoeCova]

Ive never seen a hydroboost go bad. Ive seen them leak a bit at higher mileage, but all that does is you have to top up the power steering fluid here n there.

Ya same. It’s usually air in the system or master cylinder related.

It’s also odd that it overheated while using a derale cooler.

I was told by the shop today, after the hydrobooster was replaced, that the master cylinder was bad too.

$2000 later, all was fixed.

I’m now just a few miles down the freeway & the car started shaking real bad & a lot of pedal to stay at speed.

Pull over on the highway & backing plates burnt my fingers.
Front brakes are totally locked up (maybe all?).
Waiting on a tow truck to bring us back to the closed shop.

Another hotel room & another day wasted.

More of a rant than anything. Super pissed that 2 days & $2000 later I’m still stranded.

Sounds like brake drag caused by back pressure.

 

[jjdeneen918]

Ya same. It’s usually air in the system or master cylinder related.

It’s also odd that it overheated while using a derale cooler.


Sounds like brake drag caused by back pressure.

I’m pretty sure. I don’t know the system enough to understand how it would keep constant pressure.

The shop today said the HB’s piston was free floating & leaking oil into the cabin.

 

[JoeCova]

I’m pretty sure. I don’t know the system enough to understand how it would keep constant pressure.

The shop today said the HB’s piston was free floating & leaking oil into the cabin.

I'd find a new shop

 

[jjdeneen918]

I’m back on the road again.

The shop said the rod between the hydroboost & master cylinder was too long.

They ended up cutting about 3/8” to “correct” the length for my application.

2.5 hours down the freeway & no issues.

 

[JoeCova]

I’m back on the road again.

The shop said the rod between the hydroboost & master cylinder was too long.

They ended up cutting about 3/8” to “correct” the length for my application.

2.5 hours down the freeway & no issues.

The rod was 3/8th too long and you’re just now having issues?

 

[White Stripe]

I’m back on the road again.

The shop said the rod between the hydroboost & master cylinder was too long.

They ended up cutting about 3/8” to “correct” the length for my application.

2.5 hours down the freeway & no issues.

Glad your back on the road

 

[jjdeneen918]

The rod was 3/8th too long and you’re just now having issues?

Well, it was just installed & the issue happened within a few miles…

 

[Azca]

When you get back, buy a brake booster rod adjustment tool. There should be very little to no gap between the tip of the rod and the master cylinder. You may have to get another replacement rod now if it is too sort.