94 SC Power Steering Woes Over and Over Again

tedallen

Registered User
I have been fighting issues with p/s pump leaks and failures for about 6 months now. Based on content in multiple threads in this forum, I have been in contact with several members via PM to verify part numbers, etc. I thank all of them for their responses.

The original OEM pump (I thought had failed) back in February. I got a replacement from Autozone and took it to a trusted shop to replace it. After he got it installed in the car (and before installing the p/s pulley, the shaft pulled right out of the pump. I took it back to Autozone and they could not get a replacement for several days and I couldn't wait so I headed to Advance Auto and got a pump from them. About two weeks after it was installed, leaking badly. Took it back and got a replacement. As soon as the shop started pouring fluid into it, fluid was pouring out around/from the EVO. When I looked at it, I realized the O-ring adjacent to the "tee" fitting that slides over the EVO was missing. Installed a new O-ring and everything was OK for about a couple of months. Then after the car set for a week while I was out of town, drove it about .1 mile and p/s started making very loud whine, then p/s gone completely out (and no more whine). Made it into Autozone lot and poured in fluid, which ran directly to the ground. I then drove it home and parked it.

I attempted to find the appropriate O-rings (all 4 of them) for the EVO based on input from a number of members:

Bowez
Ford O-ring part numbers:
391032-S (Interchange for 389349-S)
I was able to obtain these and they appear to be for some of the larger 3 O-ring positions on the EVO​
387571-S (No longer available)
I suspect this kit was for the smaller O-ring toward the threaded tip of the EVO​

Bowez then responded with part numbers 384975-S94 and 391032-S from an old service manual. I do not yet know if either of these are still available from Ford.​

JimmyMan
He is positive (actually went out and looked at his part number label from Autozone) that he used two of the Autozone Part # 8527 p/s pump seal kits in order to obtain the correct type and quantity of O-rings for the repair.​

He also listed AC DELCO Part # 36351210 with a quantity of two kits required.​

Kendall221
One of Kendall221's post's indicates the use of Autozone Part # 8526 for a quantity of 2.​

Can anyone who has recently performed a successful repair of this leaking nightmare tell me where they obtained the 4 correct O-rings required to correctly seal this EVO?

Are 3 of these O-rings the same identical part? If so, the O-Rings in the Ford 391032-S kit (the larger O-rings) did not correctly seal my EVO into the pump or the sleeve onto the EVO. I suspect the 2 O-rings that are positioned under the sleeve should be identical in both inner and outer diameter. However, I'm not certain this is true for the large O-ring adjacent to the sleeve and just below it toward the pump body. Obviously the smaller O-ring toward the tip is a different part.

I previously purchased a cross-reference kit for AC DELCO 36351210 from Advance Auto Parts, however, none of the O-rings in the kit appeared to be the correct size for any of the 3 larger O-ring positions (2 under the sleeve and one immediately below it) on the EVO.

A mechanic at the shop said he spoke to another shop that said these pumps were notorious for leaks and the best option was to install a plug that eliminates the EVO. Does anyone know if such a part is available that is correctly tapped for the high pressure line fitting for the OEM high pressure line?

Any and all assistance is greatly appreciated. This is driving me (and the mechanics at the shop) nuts.

Best Regards,

Ted
 
on mine the oring on the metal line was leaking where it went into the rack and pinion . the autopart store showed the replacement hose didnt include that part so i went to the junkyard and got one from a plane v6 tbird . ive never had pump issues
, when my speedometer sensor went bad the speed sensitive steering wouldnt work right and it was hard to drive at hiway speeds it steers to easy

thanks
ralph
 
I wonder how an O-ring would suddenly fail after sitting for a week.

A mechanic at the shop said he spoke to another shop that said these pumps were notorious for leaks and the best option was to install a plug that eliminates the EVO. Does anyone know if such a part is available that is correctly tapped for the high pressure line fitting for the OEM high pressure line?

That's very odd. I (and my brother) have owned 4 of these cars and never had a leaky pump once. I had a bad fitting at the rack once, but I have never even heard of a leaky pump.

Correct me if I am wrong, but ...

Doesn't the high pressure hose have the same fitting size as the EVO valve itself? So couldn't you just take the valve out of the reservoir and plug the hose right in?

Failing that, why not just get the parts (pump, line) for a Thunderbird without the EVO? My 89 base model didn't have it.

I actually like the EVO and would prefer to keep it.
 
Hi S_Mazza,

I think one or more of the O-rings were already bad and one of the O-rings they put back in (since they could not find a matching one in the p/s pump kit from Advance Auto Parts) was an a/c O-ring which did not hold up well with the p/s fluid.

I'm convinced that the leak with the original pump was actually one or more of the O-rings around the EVO.

As for the high pressure line fitting, I can't say for sure if the male fitting on the end of the line that goes into the EVO is of the same thread dimensions as the lower threaded portion of the recess in the side of the p/s pump where the EVO is installed. It might very well be. However, the way the stock line is constructed, I don't believe there is a way to maneuver it in such a manner to make the 90 degree bend that would be required to insert it into the side of the pump.

As you mention, I would prefer to keep the EVO, but in order to do so, I need to find the correct number and size of O-rings to properly seal the connection.

Best Regards,

Ted
 
I don't suppose you have the old O-rings, do you? You might be able to take them to a bearing and seal supplier and get them to match them up. Although that might be considered backwards, since the design information is obviously floating around somewhere out there.

If you need to get it running now, you might be able to just swap in the high-pressure hose from a base model. They aren't that expensive.
 
I don't suppose you have the old O-rings, do you? You might be able to take them to a bearing and seal supplier and get them to match them up. Although that might be considered backwards, since the design information is obviously floating around somewhere out there.

Unfortunately, the mechanic tossed the 3 original larger O-rings when he thought the ones I provided him from Ford would correctly replace all 3 of the larger O-rings on the EVO (the two under the sleeve that the high pressure line plugs into and the O-ring that fits against the bottom of the sleeve.

Does anyone know if the 3 large O-rings on the EVO are all the same size? I'm beginning to think the larger one below the sleeve may be larger than those that it goes over top of and that might explain the leak.

Best Regards,

Ted
 
I've owned 17 of these cars and this is the first time I have heard of such an issue with the pump. I own 4 currently and none of which have this issue...again seems like a single case overall to me (saying this based on the mechanic saying they all do it - news to me).

If it were me, I would post in the WTB section and pick up a known good used part from a fellow member and be done with it. Replacing a power steering pump on these cars isn't that intensive of a job nor should it be this darn hard to repair. Had you been closer I'd grab one from my parts shed and fix ya right up for a case.

You said "a respected shop"...they've worked on SC's before or are respected in general for quality work? An SC is a beast of it's own when it comes to shops doing repairs...this forum and your own wrenches is worth more in the long run.

-Tim
 
I've owned 17 of these cars and this is the first time I have heard of such an issue with the pump. I own 4 currently and none of which have this issue...again seems like a single case overall to me (saying this based on the mechanic saying they all do it - news to me).

If it were me, I would post in the WTB section and pick up a known good used part from a fellow member and be done with it. Replacing a power steering pump on these cars isn't that intensive of a job nor should it be this darn hard to repair. Had you been closer I'd grab one from my parts shed and fix ya right up for a case.

You said "a respected shop"...they've worked on SC's before or are respected in general for quality work? An SC is a beast of it's own when it comes to shops doing repairs...this forum and your own wrenches is worth more in the long run.

-Tim

Hi Tim,

Thanks for the response. I found a number of threads in this forum complaining of the exact same issue with leaks from the EVO, either from the O-rings under the sleeve on it, or one of the other two O-rings. that seal it off where it threads into the pump body. There are also threads regarding improperly machined EVO sleeves that never will seal correctly.

That being said, in around 240,000 miles of driving on the original pump, I never once had a leak. When the leak started 6 months ago, I've never been able to get it corrected and have gone through 3 pumps (the 4th has just been installed).

I also agree, that it is best to do things yourself, and I typically do. If I could find out the correct set of O-rings to install on the stupid EVO I would gladly do it.

Actually, if someone could supply me with a set of the 4 correct O-rings, I would gladly pay them for the parts and their time putting together the kit.

FWIW, none of the after-market auto part stores that I have checked even carry the EVO valve (they have another type of switch that is made to thread into a much smaller opening). I have no idea if this switch was ever used on any T-Bird p/s pump.

Best Regards,

Ted
 
All right, here is all the info I can find in my 1990 shop manual. (Your 1994 may vary, but this is all the info I have.)

The high pressure tube should have 2 seals. One is a flat teflon seal between the tube nut and the pump. One is an o-ring between the tube nut and the tube. The shop manual says you can replace the flat teflon seal, but not the o-ring. You are supposed to replace the tube if that leaks.

The EVO fitting should have 2 seals to the pump, both of which area o-rings. One is definitely larger than the other. The smaller o-ring is part number 387571-S1. The larger one is 389349-S.

Then there are 2 o-rings under the EVO fitting sleeve, but the shop manual doesn't talk about those. It looks from this picture (http://www.sccoa.com/forums/attachment.php?attachmentid=37644&d=1242181037 like the two o-rings are larger than the other two. It also looks like those two are not identical. So what does that leave us with, 4 different o-rings on this thing?
 
Thanks for the research S_Mazza.

The replacement pump had one separate package containing the replacement teflon seal and a small O-ring for the high pressure line. I find it interesting that the shop manual says not to replace it if it fails, but rather to replace the entire line.

I would agree that from the posted photo you get the impression that the 3 larger O-rings should all be of different sizes and that may very well be the case. However, with the EVO being tapered and presumably lying on its side when the photo was taken, along with not knowing what angle the photographer had the camera in reference to the EVO, it could be an illusion.

The larger O-ring part number you listed (389349-S) has been superseded by part number 391032-S. I was able to buy a pack of 4 of these from Ford. So, I should have the correct O-ring for the larger seal to the pump body.

The smaller O-ring part number you listed (387571-S1) is probably the same one I tried to get to Ford (387571-S) which came back as no longer available. I don't know if the "S1" suffix versus the "S" suffix would make a difference in the ability to obtain the part or not. I can certainly give it a try. Otherwise, I may be out of luck on it.

So, that leaves the two O-rings under the sleeve. There have been a number of posts regarding leaks around the sleeve and various seal kit part numbers that it supposedly takes two sets of to obtain the correct number of O-rings. That being the case, I would think they would be identical, otherwise, there should be two of the different sized O-rings in each kit. Anyone with experience resolving a leak around the sleeve on the EVO care to comment on whether the two O-rings under the sleever are identical in size or if they are different?

Thanks to all for your comments.

Best Regards,

Ted
 
Thanks for the research S_Mazza.

The replacement pump had one separate package containing the replacement teflon seal and a small O-ring for the high pressure line. I find it interesting that the shop manual says not to replace it if it fails, but rather to replace the entire line.

Maybe that O-ring is for the very end of the hose, meaning the o-ring that is supposed to sit in that machined well, according to the posts you referenced. If that is the case, I guess that makes 2 o-rings and 1 flat seal at the end of the HP line.
 
Does anyone know if the two O-rings under the sleeve where the high pressure line connects on the EVO are the same or different sizes?

Does anyone have part numbers for these two O-Rings or the part number for kit(s) that would contain both of them?

Best Regards,

Ted
 
it sucks that your still fighting with this. You mentioned a plug to eliminate the evo. Any 5.0 mustang pump has that fitting or any ford with the same style pump and no evo. It's just a straight fitting with the same thread and "well" depth. I think i kept the one that was on my last replacement pump. I will check and get back to you.
 
Some additional EVO O-Ring Information

I found some info in an old post from Discipled1 today regarding leaking o-rings on the EVO after stressing the high pressure line when dropping the sub-frame to replace motor mounts and do some other front end suspension work:

http://www.sccoa.com/forums/showthread.php?t=56014&highlight=power+steering+evo+leak

In a nutshell, his comments indicate that the two o-rings that are used to seal underneath the two ends of the swiveling sleeve that fits over the EVO are indeed different sizes, one being 7/8" and the other 1i". Here is an excerpt from the post:

When the sub frame was down, it stressed the high-pressure lign on the power steering pump, and resulted in a leak from all the o-rings on the EVO assembly. Got new o-rings for swivel fitting (thin 1in and thin 7/8in), and the two fat o-rings that seal fitting to psp. No more leak.

Given that, I suspect that the 7/8" and 1" refer to inside diameters for the respective o-rings.

Does anyone know what the difference in size would be between a "fat" and a "thin" o-ring? If I'm not mistaken, I believe there are more than two thicknesses for o-rings.

Best Regards,

Ted
 
>Given that, I suspect that the 7/8" and 1" refer to inside diameters for the respective o-rings.

I would not try to size them in that manner - buy one of each according to the 0-ring manufs. specs.

>Does anyone know what the difference in size would be between a "fat" and a "thin" o-ring?

There can be various sizes - buy one of each and test fit for best application. Have the part that you intend to 0-ring with you if you can.

There are also kits where you can buy several sizes/ranges, and kits where you can make your own 0-rings from supplied stock.

Are you sure the AutoZone kit doesn't have these? Have you tried the local Ford dealer yet?
 
>Given that, I suspect that the 7/8" and 1" refer to inside diameters for the respective o-rings.

I would not try to size them in that manner - buy one of each according to the 0-ring manufs. specs.

>Does anyone know what the difference in size would be between a "fat" and a "thin" o-ring?

There can be various sizes - buy one of each and test fit for best application. Have the part that you intend to 0-ring with you if you can.

There are also kits where you can buy several sizes/ranges, and kits where you can make your own 0-rings from supplied stock.

Are you sure the AutoZone kit doesn't have these? Have you tried the local Ford dealer yet?

The Ford dealer's exploded diagrams of the p/s pump, lines, etc. does not show part numbers for the o-rings on the EVO. When I supplied them with some of the Ford part numbers for O-rings originally supplied on this forum, they still didn't have descriptions accurate enough to tell where they were used. I tried ordering two different o-rings from them and one of the two parts is no longer available.

As for the Autozone kit, I have not tried it. There are two different Autozone kits listed in the forums (at least that I have found), one of which is apparently a special order item now. I did obtain one of the AC DELCO 36351210 kits also listed in the forum and could not find matching o-rings in it.

Best Regards,

Ted
 
'94 SC P/S EVO O-Rings - Leak is Stopped (For Now)

As of today, I have the EVO leak stopped. I never was successful finding a working combination of o-rings from the Autozone kits (8526 or 8527). I tried a kit from NAPA (Part # 7134) which I thought contained an additional o-ring not contained in the Autozone kits that had a thinner profile. This still did not work. The o-rings that fit snuggly within the grooves under the sleeve were of too high of a profile for the sleeve to pass over them regardless of how well the o-rings and sleeve were lubricated. The thin profile o-rings had too large of an internal diameter to fit correctly.

I ended up going through a selection of individual o-rings at Carquest and selecting two that were much smaller (inside diameter than what I would typically have used). However, because the tolerance between the sleeve and the EVO body is so tight, there is very little of the o-rings to be used in those positions that can extend above the channels in the EVO body.

I used a # 114 o-ring in the EVO body position closest to the electrical connector (largest inside diameter of the sleeve). I used a # 113 o-ring in the next EVO o-ring position going toward the threaded tip (smallest inside diameter of the sleeve). I used Ford Part # 391032-S in the next o-ring position toward the threaded tip (right against the end of the sleeve). I then used the smallest inside diameter o-ring from the NAPA kit (the same as the smallest inside diameter o-ring in the Autozone 8526 and 8527 kits) in the final o-ring position next to the tip of the EVO that inserts into the p/s pump body.

I hope that the o-rings under the sleeve hold up since I did have to stretch them a fair bit so that their profile would be reduced to the point where the sleeve would successfully compress them enough to fit over them. If I make it 6 months without a leak I'll feel much better about things.

Thanks to all for your input and I hope this may be of value to someone else.

Best Regards,

Ted
 
As of today, I have the EVO leak stopped. I never was successful finding a working combination of o-rings from the Autozone kits (8526 or 8527). I tried a kit from NAPA (Part # 7134) which I thought contained an additional o-ring not contained in the Autozone kits that had a thinner profile. This still did not work. The o-rings that fit snuggly within the grooves under the sleeve were of too high of a profile for the sleeve to pass over them regardless of how well the o-rings and sleeve were lubricated. The thin profile o-rings had too large of an internal diameter to fit correctly.

I ended up going through a selection of individual o-rings at Carquest and selecting two that were much smaller (inside diameter than what I would typically have used). However, because the tolerance between the sleeve and the EVO body is so tight, there is very little of the o-rings to be used in those positions that can extend above the channels in the EVO body.

I used a # 114 o-ring in the EVO body position closest to the electrical connector (largest inside diameter of the sleeve). I used a # 113 o-ring in the next EVO o-ring position going toward the threaded tip (smallest inside diameter of the sleeve). I used Ford Part # 391032-S in the next o-ring position toward the threaded tip (right against the end of the sleeve). I then used the smallest inside diameter o-ring from the NAPA kit (the same as the smallest inside diameter o-ring in the Autozone 8526 and 8527 kits) in the final o-ring position next to the tip of the EVO that inserts into the p/s pump body.

I hope that the o-rings under the sleeve hold up since I did have to stretch them a fair bit so that their profile would be reduced to the point where the sleeve would successfully compress them enough to fit over them. If I make it 6 months without a leak I'll feel much better about things.

Thanks to all for your input and I hope this may be of value to someone else.

Best Regards,

Ted


Hey Ted,

Just happened to see your posts this morning. Sorry I didn't see them when you were trying to get this fixed. Hopefully, it's still not leaking. I've got a '95, and the EVO can be a pain. I would not recommend doing away with it, because if you do, you will have full power steering all the time, and the steering becomes very touchy, and not fun to drive on the highway.

I've found that Lucas Power Steering Stop Leak also does a good job at slowing down these leaks. You can also add it as a preventative. Also the correct power steering fluid for this system is Type F ATF.

I can confirm that the 8526 kit has the correct o ring in it that is under the EVO sleeve. Unfortunately, it only has one in the kit, so you end up buying two kits. I think the other two o rings on the tapered part of the EVO are in the kit, but can't remember. I don't ever recall ever having any issues with replace those, or else having leaks due to those smaller o rings. My leak problems were due to the ones under the sleeve. Last time I bought that kit, Autozone had it in stock, but that was several years ago, so they may not anymore. I keep a couple extras handy in my parts stash just in case I need them. I looked online, and Rockauto has them for $8.00.

Also, one thing that I always do is to coat these o rings with Vasoline. I read that on one of these forums.

David
'95 SC
 
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