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Home » Public Forums » GMCnet » [GMCnet] Subject: Re: Brake problem, badly need suggestions
[GMCnet] Subject: Re: Brake problem, badly need suggestions [message #350589] Mon, 09 December 2019 16:48 Go to previous message
THOMAS R WHITTON is currently offline  THOMAS R WHITTON   United States
Messages: 47
Registered: September 2016
Karma:
Member
Appreciate your suggestions.  I'm at my wits end.  
Earlier this year the brakes on our GMC faded badly on a panic stop.  I avoided a catastrophe and, in an effort to remedy the situation, I decided to install the Hydro-Boost system.  It's now installed but something isn't right.  I'm not sure at this point if the problem is the Hydro-Boost system or the normal brake system, beyond the Hydro-Boost.  (For those not familiar, Hydro-Boost simply replaces the vacuum booster with a hydraulic ram. Everything else in the braking system remains the same.  Hydro-Boost provides more pressure to the master cylinder, which should be providing much better braking.)  The coach should stop almost like a new van but, unfortunately, it doesn't.  I've cancelled three trips trying to get this problem resolved but the brakes still are not safe for a trip.

The problems I'm having:
Inadequate braking capability in normal driving situationssuch as traffic lights, slowing for traffic, etc.
Brakes are capable of good stopping in hard braking or panicsituations with maximum pedal effort but the brake light comes on.

Limited gradual braking with light to medium pedal effort (too much effort in normal stop and go traffic).

Excessive pedal effort to brake normally.




What's been done and added:
Rebuilt Hydro Boost unit originally from nineties Astro Van.
Custom mounting flange. 

Custom rear clevis.

Custom mounting on brake pedal cylinder.

Power steering cooler from donor Ford vehicle.

New hoses to and from power steering pump, Hydro Boostunit, power steering unit and cooler.

Rebuilt original calipers from donor GMC motorhome.

New front brake hoses.

New front stainless-steel brake lines from master cylinderto distribution valve.

New distribution valve.

New master cylinder.

New power steering fluid reservoir.

New power steering pump.

Four new rear wheel cylinders. 

Four new brake drums.

Front P30 calipers were replaced with restored original calipers with yellow sticky pads.

Good performance friction rear brake shoes were reinstalled.

System has been thoroughly pressure bled on all six wheels multipletimes.




Tom Whitton

26 foot updated GMC

Paducah, KY

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