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Power steering and brakes on one pump?

3462 Views 11 Replies 10 Participants Last post by  JSquire
My power steering pump blew out, blowing powersteering fluid everywhere and a very loud humm while the truck is running, when i hit the brakes it humms even louder and if i hit them hard it will scream a little bit... are these pumps one in the same? or did i happen to just blow a power steering pump and a break booster all in just one moment?:banghead:
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someone should be able to tell you for sure, but I think the vacuum pump runs both the power steering and the brakes, so losing your power steering could have damaged the vacuum pump.
 

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there is no vacuum booster for the brakes, only hydraulic pressure from your power steering pump.

sorry to hear about your situation, not fun
 

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do a search...
If your puking out out the PS resivoir, more than likely the Hydroboost is shot, it provides power brakes, there is an acculimator inside that stores hydralic(best description I can give) when it fails, it dumps the extra fluid overfillng the resivori, causing the pump to cavitate and groan, usually most diagnois wrong thinking their power steering pump is faulty.

Most trucks will exibit the same fault, if the fluid has never been changed, 8 outta 10 times replacing the fluid with a quality PS fluid(generally synethic) will cure the problem, as most times it surfaces on a cold (usually bitter cold day) first startup of the day.
if you cant source a synthetic fluid, may report good results with fresh powersteering fluid and Lubguard added to it

HB can be changed in 15mins WITHOUT unhooking the mastercyl brake lines (NO need to bleed the brakes) just remove to bolts that hold the MC to the HB and gently move to the side and tie it to something to keep it from moving while you unbolt the HB
 

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my truck is doing exactly what nickg is saying. What is the hyrdoboost? Where is it located at? and what is the MC? Please help me fast.
 

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Hydrobooster

Your truck has Hydroboost brakes, instead of a big vacumm booster that most people are familar with there is a Hydralic booster powered by power steering fluid from the power steering pump. It is located behind the master cylinder for the brakes. The master cylinder is bolted to it. Pretty easy to replace there are 4 15mm bolts inside the truck on the firewall behind the brake pedal and a clip that holds the control rod to the brake pedal, 4 bolts that hold the master cylinder on, and 3 hydralic hoses, the master cylinder can be carefull moved out of the way for removal without removing the brake lines.
 

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My truck did the same thing. Your power steering pump is shot. YOu can try flushing the fluid out and putting senthetic in it but the pump is probably shot. There is nothing wrong with your hydroboost. Your Powersteering pump, not your vacum pump, send hipressure hydrualic fluid to the gear box for your steering as well as to your hydroboost for power brakes. The power steering pump is simple to replace just a little tricky to get to all the bolts. I heated up a 15mm wrench with a torch and bent it on a 90* to get to the bolt under the injector pump.
 

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Yes you will need to rebleed it. Im not real sure how to do it properly. But i just started turning the wheel in park with the truck running. It is very hard to turn at first but then it gets better. Turn it back and forth all the way, i idled mine up a little bit when i did it. I got it pretty good, it was still moaning a little bit, but after about 30 miles it was all cleared up and going great. Powersteering pumps go out alot in the winter, im not sure why?
 

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I have a 99 Cummins 2500 and just heard symptoms today. It was cold today, 4 degrees F.
LOUD moaning power steering, especially moving the steering wheel and braking. I also had the heat on HIGH. When I would make a tight turn, the heater blower would go low as the groaning increased. As the groaning lessened, the blower fan blew stronger. It was 4 degrees F today, and as the truck warmed up, symptoms lessened. Does this sound more like a PS pump? Or should I trouble shoot the PS pump, PS pump screen, and hydroboost the same way? Please help!
 
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