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kellyfettes · 11-04-2020, 04:01 PM

I have a Chevy 454 p30. 1988 Holiday Rambler Imperial. I was having brake problems. No fluid getting to the back brakes. So I had it towed to the shop. I had already bought a brake hydroboost. They installed that and a new master cylinder. There is now fluid to the back brakes, but the pedal is super hard to push. They said there is a rear brake booster. Anyone know about that? Also I wonder if they didn't seat the hydroboost correctly and the brake pedal is pulling hard on the booster. Anyone have this experience or advice?

EyezOpen · 11-04-2020, 08:03 PM

Quote:

Originally Posted by kellyfettes

I have a Chevy 454 p30. 1988 Holiday Rambler Imperial. I was having brake problems. No fluid getting to the back brakes. So I had it towed to the shop. I had already bought a brake hydroboost. They installed that and a new master cylinder. There is now fluid to the back brakes, but the pedal is super hard to push. They said there is a rear brake booster. Anyone know about that? Also I wonder if they didn't seat the hydroboost correctly and the brake pedal is pulling hard on the booster. Anyone have this experience or advice?

First stop change all the rubber brake lines, they rot from the inside and those debries just happen to block the pressure in the line.

MinntoMich · 11-04-2020, 09:14 PM

I have Hydroboost on a 93' P30. Its not a Holiday Rambler but I can say with certainty that there is no rear brake booster. Never seen or heard of one. What a stiff peddle tells me is that your Hydroboost is not storing a charge to operate your power brakes. I think if your power steering pump, power steering fluid level and AutoPark (if you have one) are okay then you've got a problem with the Hydroboost itself. Dunno. Is your peddle physically binding up or jamming against something or is it just a real hard push, like vaccum boosted brakes when your car stalls out?

Hydroboost brakes do have a different feel to them but the only time I had a hard peddle was when I had air in the PS system and needed to adjust the AutoPark brake shoe and actuator rod.

A brake line can rot from the inside and act like a check valve. Rare, but does happen. Suprised the shop you were at didn't suggest replacing them.

Jyrocharlie · 11-04-2020, 10:39 PM

1989 p30 454 hydro boost

When I tried to drive mine like that, it kept building pressure till the calipers started to lock up. I tried 2 new master cylinders, both did the same thing. The master cylinder wasn't releasing the pressure when you let off the brake peddle, it stayed hard and had zero free play. I loosened the bolts on the master cylinder that attached it to the hydro boost unit and placed one flat washer between the master cylinder and the hydro boost unit on each bolt. Tightened it back up and drove it thousands of miles without a problem. It seems the new cylinder wasn't releasing the fluid back to the reservoir because the port that allows that wasn't uncovered enough. Allowing a tiny amount of free play in the peddle allowed that port to uncover.

kellyfettes · 11-05-2020, 08:08 AM

Anyone have experience with a shop replacing the hydroboost and master cylinder? Talking to the shop yesterday, once again, I asked for a close price. They told me they have 10 hrs labor into it. Putting on new parts and getting fluid to the back. All which they did easily. Then Weds morning they told me about the hard pedal, which still isn't fixed. They are charging $94 an hr. When he told me that last evening I told told them to stop. Anyone have an idea on what it should normally cost?

kellyfettes · 11-05-2020, 08:45 AM

This is the extra booster they are talking about. It is behind the stairs.

Jyrocharlie · 11-05-2020, 08:51 AM

Chevrolet C70 rear brake booster? https://www.google.com/search?rlz=1C...4dUDCA0&uact=5

Jyrocharlie · 11-05-2020, 09:05 AM

https://www.youtube.com/watch?v=2RxCrqTQ9SU

Jyrocharlie · 11-05-2020, 09:13 AM

https://www.youtube.com/watch?v=WnhvCu1zU88

GypsyR · 11-05-2020, 09:41 AM

I have a different model and make of coach but on mine that "extra booster" is actually for the completely separate braking system for my tag axle.

kellyfettes · 11-05-2020, 12:45 PM

So I got it down to $757. The bitch is, it's still not fixed. And when we went to pick it up, they didn't have the motor cover on. Just pissed me off.

kellyfettes · 11-05-2020, 12:50 PM

So got to the shop. They didn't have the dog house on. Just added to frustration. Then, to top it off, the brake pedal is going to the floor. They are not hard, like they had stated to me on the phone several times. So what they did do is put on the hydroboost, that we had already purchased, and put on a new master cylinder. Fluid to the back brakes but they aren't working. Said it has to do with the tag axle booster. We just slowly drove it home. $757 and still not fixed.