Hydroboost noise

[84 M1008]

My hydroboost unit has a loud buzzing noise sometimes. It happened again yesterday and the strange thing about it is the belts stopped squealing when the buzzing stopped. Belt squealing is common with CUCV trucks and is associated with the dual alternator setup when the engine is cold. Any ideas?

 

[HotRodPC]

First things first, Have you checked the fluid in the pump reservoir lately???

 

[84 M1008]

Yup, it's full and steers lock to lock with no problem.

 

[bucket]

Buzzes all the time, or just when braking? I had one make a buzzing type noise while braking, it ended up being a failing pump.

 

[84 M1008]

Just when I start it. The usual screaming belts, and every so often I get the buzz. It actually vibrates through the dash and stops along with the belt noise. I don't get it .

 

[Snoots]

P/S fluid foaming?

I wonder if it's the reserve cannister loading? DON'T TRY TO REMOVE IT! At least without following instructions. I have no idea how to.

I'd put some dressing on the belt and check the tension before I dug into anything else.

 

[bucket]

P/S fluid foaming?

I wonder if it's the reserve cannister loading? DON'T TRY TO REMOVE IT! At least without following instructions. I have no idea how to.

I'd put some dressing on the belt and check the tension before I dug into anything else.

With the truck off, pump the brakes until the assist pressure is all gone. Then it's safe to remove. There might be a buildup of gunk and crap behind it.

 

[84 M1008]

Thanks guys, the power steering lines look like they need replacement. I'm thinking they might be collapsed.

 

[Snoots]

X2 on buckets' statement.

If it's a collapsed line, that would likely be a return/suction line and that would lead me to believe an obstruction or air in the line.

Have you ever used ATF as a fluid? If so, drain it all and replace it with PS fluid. ATF has the habit of foaming.

Do you have a PS fluid cooler? If not, get one added.

If you do change the fluid I would advise to do a system flush with a lot of PS fluid. That, if you think the hose(es) are collapsing, replace them first.

 

[Snoots]

Then it's safe to remove.

Is that a 'push-in-and-twist' or screw off, or what?

 

[bucket]

Is that a 'push-in-and-twist' or screw off, or what?

There's a little hole that you stick a pick tool into, to release a snap ring. I don't recall the exact details, but it's fairly simple.

The canister has a nitrogen charge in it, but it's self-contained. It acts as a storage tank for PS fluid, it's forced into there by PS pump pressure and overcomes the pressure from the nitrogen. Then when the pump stops, the pressure from the nitrogen keeps enough pressure in the system to get a couple more pushes out of the brake pedal.

 

[HotRodPC]

There's a little hole that you stick a pick tool into, to release a snap ring. I don't recall the exact details, but it's fairly simple.

The canister has a nitrogen charge in it, but it's self-contained. It acts as a storage tank for PS fluid, it's forced into there by PS pump pressure and overcomes the pressure from the nitrogen. Then when the pump stops, the pressure from the nitrogen keeps enough pressure in the system to get a couple more pushes out of the brake pedal.

Kinda like the one check valve in the vac line to the vac booster that so many people remove thinking it's not needed.

 

[bucket]

Kinda like the one check valve in the vac line to the vac booster that so many people remove thinking it's not needed.

The filter or the check valve? The check valve is in the hose nipple at the booster. The inline filter is seemingly useless, GM didn't even put them on most of the stuff they built.

 

[HotRodPC]

The filter or the check valve? The check valve is in the hose nipple at the booster. The inline filter is seemingly useless, GM didn't even put them on most of the stuff they built.

Is it possible a filter is also a check valve too? I know I've taken a filter out before and it worked like it didn't have a check valve once I did that. The plastic going into the booster that I've always thought was a check valve was a complete blow through either direction. No check valve to it at all.

 

[bucket]

I've only seen the check valves in the booster nipple.

I'm wanting to say that the filter was only used on 80's Quadrajet equipped cars and trucks, but I've also never tried to narrow that down. Could be others that used it. I can't remember if my TBI motors have them. I know my TPI stuff hasn't had a single filter.