How To: Power Steering Hydroboost Flush

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Freedom Motorsports

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How To DIY Power Steering Hyrdoboost flush.



The issue/complaint: Either a whining power steering pump or tight steering during turning or spongy braking can be complaints associated with the need to flush the power steering fluid.



Tools Needed: Channel Lock/Needle Nose/Clamp Pliers

Drain Bucket

6-8 feet of 3/8 fuel/heater hose

1.5-2 full quarts of power steering fluid.



To get started Place a rag under the power steering fluid return line at the top of the hydroboost unit. This rag should cover the hydroboost unit, it will catch the power steering fluid you lose while removing the return line.

IMG-20110802-00359.jpg


Then use either channel lock, needle nose or clamp pliers to squeeze the clamp and twist the return line to losen it for removal. The line can be super tight, if not stuck in place if it has been a while since the last flush, so be very careful when pulling it off to avoid hurting your hand against the cowl.

IMG-20110802-00361.jpg

Place a bolt in the return line as a plug to avoid power steering fluid leaking all over the place.

IMG-20110802-00362.jpg

Connect your 3/8 heater/fuel hose to the hydroboost unit at the return line plug and hang it over the side of the quarter panel into your drain pan. I personally use a small two foot piece of 3/8 hose that I slide into a 5/8 hose that hangs into the drain pan, the added weight of the 5/8 hose helps to keep the hose from moving too much in the pan once the fluid begins to pump out of the hydroboost unit.

IMG-20110802-00363.jpg


Start your engine and pump your brake pedal until you first begin to hear the power steering pump whine a little. Then turn the truck off and refill the power steering fluid reservoir. Then start the engine again and pump the brake until the power steering pump begins to whine. Repeat this until you see the fluid draining into the pan begin to change from a dark braon to a light brawn color. Although power steering fluid is mostly clear, it will not get completely clear in the pan.

IMG-20110802-00366.jpg

On your final refill of the reservoir make sure not to overfill it. Add small amounts of fluid a little at a time while checking the level in between to ensure that your level is just right. Then reinstall the return line to the hydroboost unit and you are done. Now test drive the truck and see if your power steering and braking is any better than before. I'm betting it will be.



Good luck and get to work....



.
 
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Freedom Motorsports

Freedom Motorsports

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Mine is an 04', the pics in the diy above are on a 2004 Duramax. But the Hydroboost on them is the same set up.
 

jeffyrc

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I'm having the same problem, my power steering whine's and is kinda loud. Drives me nuts
 
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Freedom Motorsports

Freedom Motorsports

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I'm having the same problem, my power steering whine's and is kinda loud. Drives me nuts

For as little as it costs to do the flush it is WELL worth the time. Makes a big difference in the overall feel of the brake pedal and the steering. If your pump is whining loud already however, flushing may or may not solve that. It could be time for a new pump, but the flush is definitely the place to start.

changed the fluid tonight, what a breeze, and the petal really does feel better. so much for needing brakes :Handshake:

It is definitely one of the easier things to do as maintenance goes. :cheers:
 

2006Tahoe2WD

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Thanks for posting this. I did this on Saturday with two containers of fluid. I think I need to redo with more fluid. A 3/8" hose is too big - I need to get the next size smaller. We heard the whine noise when the brake was pressed down but when it returned up the noise went away. Was hard to estimate how much was purged until a refill - maybe 5 oz. Should I keep pumping the brake until the whine keeps going when the brake pedal comes back up? This would provide a better flush (more fluid per refill). Combining this with a brake fluid flush - my brakes hit very near the top now.
Thanks again.
 
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Freedom Motorsports

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I would recommend against continuing to pump the brake pedal when you hear the whine just because it could potentially cause harm to the PS pump. That whine is the gears in the pump trying to pump without fluid. You could also wind up with air pockets in the PS system as well.
 

reedal

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Sorry to bump this oldie, but could the "Service Brake Booster" message on the DIC possibly be caused by the hydro boost needing to be flushed? I don't have any whine when turning except once in a blue moon while turning the wheel backing out of a parking spot. I've looked up the message and all it says is the cause of the message on everything I've found, but not a solution. Just trying all avenues. Thank you :)
 

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