# NHTSA Preliminary Evaluation PE87038
> **HYDROBOOST FAILURE** · Opened 1987-07-09 · Closed 1988-01-28
## Investigation
- **Action number:** PE87038
- **Type:** Preliminary Evaluation
- **Open date:** 1987-07-09
- **Close date:** 1988-01-28
- **Manufacturer:** General Motors, LLC
- **Affected makes:** BUICK; CADILLAC; CHEVROLET; OLDSMOBILE; PONTIAC
- **Affected components:** STEERING
- **Affected model years:** 1984, 1985, 1986
- **Affected (make, year) variants:** 24
## Summary

SUBJECT VEHICLES:CAPRICE, CAPRICE CLASSIC, CUSTOM CRUISER, DEVILLE,ELECTRA, ESTATE WAGON, FLEETWOOD, LESABRE, NINETY-EIGHT, PARISIENNE,PARK AVENUE.(ALL 1984-86 GM VEHICLES EQUIPPED WITH HYDROBOOST II SYSTEMS)ANALYSIS:CONSUMER COMPLAINTS ALLEGE SEVERAL PROBLEMS INVOLVING THE POWERSTEERING AND POWER BRAKE SYSTEMS OF THESE VEHICLES.THESE PROBLEMSINCLUDE: POWER STEERING FLUID LOSS, POWER BRAKE FLUID LOSS, LEAKAGE FROMTHE HYDRO-BOOST II POWER BRAKE BOOSTER, BROKEN BOOSTER SEALS, AND MASTERCYLINDER FAILURE.ALL PROBLEMS SEEM TO BE RELATED TO THE HYDRO-BOOST IIPOWER ASSIST SYSTEM, IN WHICH THE WORKING FLUID PROVIDES POWER ASSIST TO BOKE BOOSTER.THE EFFECT OF THESE PROBLEMS COULD BE A LOSS OF STEERINGCONTROL AND/OR BRAKE EFFECTIVENESS.STATUS:THE VOLUMINOUS AMOUNT OF DATA SUPPLIED BY GM IS PRESENTLY BEING CODED BY A CONTRACTOR AND SHOULD BE COMPLETED BY 12/30/87. GM DATA INDICATED A 50% WEIBULL DISTRIBUTION FAILURE AT 50K MILES FOR THE PISTON PUSH-ROD SEAL. THIS PE LOOKS TO HAVE AN EXTRODINARILY HIGH FREQUENCY, ALTHOUGH THE SEVERITY APEARS TO BE LOW.SHOULD BE INTERESTING DISCUSSING THIS FOR UPGRADE/CLOSURE.===

## Source
- [NHTSA ODI investigation page](https://www-odi.nhtsa.dot.gov/owners/SearchResults?searchType=ID&targetCategory=I&searchCriteria.nhtsa_ids=PE87038)
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