# Power Steering Fluid blowing out of cap



## jtwoods4 (Dec 22, 2011)

69 GTO. Hydratech brake assist unit that uses the stock power steering pump and fluid as the hydraulic fluid. After driving the car hard (lots of turning and braking) I open the hood and find power steering fluid has blown all over the driver side of the engine compartment.

Fluid is coming out from around the cap and through the pressure relief hole in the cap.

I made sure I did not over fill the power steering fluid when I installed the hydratech and plumbed it to the power steering pump. Any ideas what would be causing this?


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## BearGFR (Aug 25, 2008)

I've you've been driving "spiritedly"  my guess is that there was air trapped in the system and that's what caused the mess.

There's a procedure for purging it I've got someplace... basically you fill it up, engine off.
Start it up let it run just a second or two without touching the steering wheel, then shut if off. Top off the fluid... repeat until the level doesn't seem to be dropping. 
Next start it, turn the wheel just a tiny bit - shut off - repeat. Keep sneaking up on it, turning the wheel just a little more each time until you get to the point where you can turn the wheel lock to lock with the engine running and the fluid level doesn't drop.

At that point you should have all the air out of the system.

Bear


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## jtwoods4 (Dec 22, 2011)

Hmmm ok. I will give that a shot. Thanks again Bear, you never fail to come to the rescue.....


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## FlambeauHO (Nov 24, 2011)

Seems like I heard another one on hear a while back that said to turn it lock to lock a few times with the engine off. But I could be wrong....


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## BearGFR (Aug 25, 2008)

FlambeauHO said:


> Seems like I heard another one on hear a while back that said to turn it lock to lock a few times with the engine off. But I could be wrong....


There's a procedure for purging most of the old fluid out of the unit. You disconnect the low pressure return line and put it down below the unit into a container. Then you turn the wheel lock to lock, engine off, to drain the unit - as well as it can be without disassembling it anyway.

Bear


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## 67GTOCoupe (Mar 6, 2013)

I have always used the lock to lock system on all cars with good luck. There are some designs though that love to trap air. Like the other have said I like to cycle the wheel lock to lock then hold it locked to one side and shut the engine down. Wait a minute then statrt it back up and cycle it agian then hold it to the other side full lock and shut the engine down again and wait a bit. Also remember that the fluid does expand. Full hot and full cold are different levels.
Sounds like you just have either a simple case of a burp or you just overfilled it from the start.


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## jtwoods4 (Dec 22, 2011)

Well after doing some more research I have found out that the the foamed fluid was due to the hard driving and the hydratech hydraulic brake assist unit. The power-steering fluid is now doing double duty on the steering and the brakes. This causes the fluid to over heat and boil over causing the fluid to also foam. Here is a video of the solution. Anyone have any experience with this? I hope it works, the cooler looks very wimpy.

69 GTO - Dorale 13210 Power Steering Fluid Cooler - YouTube


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## SANDU002 (Oct 13, 2004)

If you are going to autox or any high speed event, I would recommend you switch to a racing fluid which have higher boiling temperatures. Royal Purple or Redline are very good.


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## 67GTOCoupe (Mar 6, 2013)

I owned a 84 Buick Regal T-Type with the hydro-boost brake system for several years. I never had any problem at all with standard power steering fluid puking out.
It sounds like adding a small cooler is more in order as some others have suggested.
You should not have to spend to much on one. Almost every car build in the last 20 years is equipt with some type of power steering cooler. A trip to the bone yard with some basic measurements of the place where you would like to install it should be all you need. Most factory installations of them are usually places on the front of the radiator support just below the radiator. They are always installed on the return side. This should make installation even easier as one you find a good location you only need a couple of feet of standard power steering return hose. Run the return hose out of the gear box to the cooler then back out of the cooler to the pump. The cooler also has the added effect of enlarging the overall capacity of fluid the system hold which also helps in cooling!
Lets us know how you make out. Also just a heads up when you are running a hydro-boost brake system be aware of one thing. If the car ever stalls while you are driving it you better have some strong legs because the amount of effort needed to stop the car without the boost of the power steering pump is enormous!


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## Rukee (Feb 8, 2007)

jtwoods4 said:


> Well after doing some more research I have found out that the the foamed fluid was due to the hard driving and the hydratech hydraulic brake assist unit. The power-steering fluid is now doing double duty on the steering and the brakes. This causes the fluid to over heat and boil over causing the fluid to also foam. Here is a video of the solution. Anyone have any experience with this? I hope it works, the cooler looks very wimpy.
> 
> 69 GTO - Dorale 13210 Power Steering Fluid Cooler - YouTube


I agree, it looks wimpy. Why couldn't you use an auto tranny aftermarket cooler? You can pick them up at any auto parts store for around $35.00.


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## 67GTOCoupe (Mar 6, 2013)

Rukee said:


> I agree, it looks wimpy. Why couldn't you use an auto tranny aftermarket cooler? You can pick them up at any auto parts store for around $35.00.



Also a good option. The transmission coolers tend to be a bit bigger that the power steering coolers use by most manufactures but if you have the room it would definetely get the job done.


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## jtwoods4 (Dec 22, 2011)

I called Derale and they said that cooler would not work well for autocross, to small. So here is the new one Derale 13220. Its a transmission frame rail mount cooler. But they said it would work well for hard driving on the track.

Derale 13220 Power Steering Cooler - YouTube


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## stan 49 (Aug 30, 2019)

how should you check the power steering fluid on a 1967 gto hot? cold? running or not?


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