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1990 Suburban..brakes & warning light
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PK
New User
Feb 26, 2009, 12:06 PM
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1990 Suburban..brakes & warning light
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1990 Chevy Suburban, 350, 240,000 on truck, maybe 80,000 on this engine.
About eight months ago I broke a belt and of course, all warning lights came on as I drained the battery. After replacing it, I noticed that the brake light was on. Fluid level was full. Being an older work vehicle I chalked it up to age. For about a month or so the light would flash in a sequence of one long followed by five short blinks and then it quit coming on.The brakes felt good for the most part, though occasionally "clunking" from the rear on low speed stops when pedal pressure was released some for smooth stopping. Today the light came back on and there was a short bout of spongyness that quit. Light is still on, fluid level is good, should I bleed system, and If so what is the order ?
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Loren Champlain Sr
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Feb 26, 2009, 5:31 PM
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Re: 1990 Suburban..brakes & warning light
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Brake bleeding sequence is: LR, RR, RF, LF....But..Does this have ABS? Hydro-boost? Have you had the brakes inspected? If it is full of fluid and the hydraulic system has not been breached, it shouldn't need bleeding. Could be as simple as the rear brakes are severely out of adjustment or just plain worn out, causing excessive pedal travel.
Loren
SW Washington
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PK
New User
Feb 26, 2009, 7:46 PM
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Re: 1990 Suburban..brakes & warning light
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I have not pulled the wheels to inspect the brakes, I didn't understand the fluctuations of good then poor performance followed by good performance. I've owned this as a work vehicle for just under a year and to be honest assumed it had ABS. I am not familiar w/ hydro boost. My shade tree days passed w/ leaded fuel in the precomputer days. I find it easier to work on our '64 230sl ( in low level restoration) than the vehicles we drive now. I was confused by the dash light coming and going w/ the performance and was hoping for some insight and a starting point.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 27, 2009, 4:31 AM
Post #4 of 6
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Re: 1990 Suburban..brakes & warning light
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To add to Loren's suggestions:
Hydroboost is using PS pump and fluid for brake assist instead of a vacuum diaphragm. Just look for which type it has - I dunno.
How about parking brake? Cables can be sticky and if parking brakes has been used and didn't retract fully it could leave a light on dash or flicker. If they didn't fully retract brakes actually might feel firmer and better under certain circumstances and when suddenly if they could retract brake would feel spongy OR more like they needed adjustment or replacement. Note: Parking brake is using the rear shoes by cable instead of hydralically but the same shoes.
They really need a thourough inspection, clean, lube and adjust - replacment as needed,
T
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PK
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Feb 27, 2009, 3:05 PM
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Re: 1990 Suburban..brakes & warning light
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Thanks for the responses gentlemen, I guess we'll find out more Sunday when the rain quits and I can inspect the rears. I haven't used the E brake, but did pull the handle to see if the light would go out. Had a '64 Falcon in the old days ( that I paid $30.00 for ) that the button for the light would stick on behind the E brake.
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Loren Champlain Sr
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Feb 27, 2009, 4:03 PM
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Re: 1990 Suburban..brakes & warning light
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I didn't think to ask, but does this have drum or disc brakes in the rear? Pretty sure, being a '90, that it's drum, but if disc, the only way the rear brakes adjust is by using the emergency brake. When you depress the brake pedal and it's low, if you pump the pedal a time or two, does the pedal feel nice and high? Or if you depress the parking brake, does the pedal feel better? If so, I'd suspect the problem to be in the rear brakes. If the brakes are worn out or severely out of adjustment, the brake pedal travel will be more than normal and the system may be seeing that as a loss of pressure, illuminating the warning lamp. Of course, it could be the master cylinder, but start with the brake inspection/adjustment/replacement, first.
Loren
SW Washington
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