Power Steering Leak

[sixers229]

I have a very slow leak in my power steering rack. I top it off about once a month or so. Are there any products with "stop leak" that would be ok to put into my car. I currently use this http://www.britishcarpartsco.com/images/Pentosin.JPG power steering fluid. I just don't want to put anything into my system that could potentially screw up something else and cost me more money in the long run (aka power steering pump, or lines)

Thanks for the help!

[old guy]

Read post #5 in this thread. If it is already leaking you have nothing to lose. Clicky click

[sixers229]

I was to make sure it wont damage any other part of the steering system...i.e. the power steering pump.

The audi uses a CHF type fluid and I do not believe it is compatible with the ATF which is what Lucas Stop Leak is.

[S4King]

My S4 is currently at the shop ATM. Getting some hoses replaced due to them bursting. I don't recommend using any type of stop leak since the detergents used in the chemical might cause more of a damage later on.

[sixers229]

After searching the forum I have found many posts with people claiming they used Lucas Stop Leak and it worked wonderfully. I mean the rack is already damaged so as long as I don't damage any other parts of the system I think it might be worth a try. Has anyone used this before and how exactly did you do it? Can anyone speak from experience?

[old guy]

I was to make sure it wont damage any other part of the steering system...i.e. the power steering pump.

The audi uses a CHF type fluid and I do not believe it is compatible with the ATF which is what Lucas Stop Leak is.

Excellent point, but I believe the two are compatible. Here is some info from Blauparts on the subject:


Can You Mix CHF 7.1 Non-Synthetic Mineral Base Hydraulic Fluid With CHF 11S Synthetic Mineral Base Audi Hydraulic Fluid?


There has been a good measure of controversy over this question. Here is what our own experience shows. Over the last decade we've had no compatibility problems mixing the CHF 7.1 non-synthetic mineral base fluid and the CHF 11S synthetic based Audi hydraulic fluid. No problems with our own vehicles and no problems with our customers vehicles. Our success in mixing the 2 Audi hydraulic fluids coincides with the Audi tech bulletin 48-89-T07 issued in November 1989. It states "The new [synthetic Pentosin 11S] and old hydraulic fluid [non-synthetic Pentosin 7.1] can be mixed if necessary ... the part number [remains] unchanged." So according to Audi, you can mix the 2 Audi hydraulic fluids. Even though the composition of the fluid changed (CHF 11S synthetic mineral oil vs CHF 7.1 non-synthetic mineral oil), Audi didn't even change the part number. All 1990 - on Audi models have come filled from the factory with the synthetic CHF 11S Audi hydraulic fluid (G002000). Please Note: Never mix generic hydraulic fluid or other fluid with the CHF 7.1 or CHF 11S Audi hydraulic fluid (G002000). If you or someone else did, flush the Audi hydraulic fluid as described below.


The Lucas Stop Leak works with mineral based systems so in theory it should work with the Pentosin CHF. Ultimately it's your decision.

[sixers229]

So do I just add a bottle of lucas stop leak with the Pentosin fluid that is already in the system?

[old guy]

So do I just add a bottle of lucas stop leak with the Pentosin fluid that is already in the system?

I cannot say from first hand experience that it will work and not cause any issues. I did just spend about 15 minutes Googling up anything I could find on compatibility issues. The Lucas site wasn't very helpful. What I found was a lot of "I read this or I heard that" about the compatibility. The best information I could find was what I copied from the Blauparts site. As stated above, ultimately it's your decision. If my power steering rack started to leak I would most likely try it. Worst case scenario is that it gets worse and I had to replace the rack (that was leaking anyway).

[sixers229]

Yea im definitely going to try it. I am just not sure exactly the process of doing it. Do I need to drain the system and fill or can I just add the stop leak to the system the way it is?

[old guy]

Yea im definitely going to try it. I am just not sure exactly the process of doing it. Do I need to drain the system and fill or can I just add the stop leak to the system the way it is?

Just use something like a turkey baster to remove enough fluid to be able to add the correct amount of stop leak.

[sixers229]

I haven't actually purchased it or read the directions but I am assuming I just add the bottle to my system. I'll look into this tomorrow.

[cdn20valve]

In my experience it takes 1.5 bottles of the stop leak. They are very small bottles. Once it's low, add some lucas stop leak. Then drive the car, but AVOID lock to lock turns. Don't hold it to the end "soccer mom minivan style". It will most likely leak out again, this is when you add the remainder of the bottle. That was it.

The Lucas stop leak in my B6 has been holding for about 2.5 years. :)

My other Audi, the B5, just started leaking yeterday. Lucas stop leak FTW. If I had to replace both racks, I'd be in it for $1600.00 cdn + labour and alignment! SHIT!

[black97]

Lucas stop leak worked for me so far. about 6 months and topping up the resevoir when it got low, aout 3/4 of the bottle she seems to be holding steady.