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Discussion Starter · #1 ·
Hi
I am currently trying to solve a PSF leak from somewhere around my steering rack.
On initial glance I assumed it was a coolant leak, however after a frustrating hour of looking for an active leak from the coolant system, I was surprised at my stupidity at this point to realise that it's PSF.

I've not really messed with the power steering system before so I am after some advice. The lines that go into the union on the rack appear to be dry. You will see in the attached photo that the collection of fluid appears to be around the bottom (unknown) bolt and just above, also travelling back on to the subframe.

There doesn't seem to be much literature out there about power steering system and the rack...
  • What is the bolt in my picture with the question mark?
  • Is the locking nut area I have identified as preload correct, or does it have a different purpose?
  • What areas can leak PSF on this area? (apart from the lines, these don't seem to be leaking but I will double check tomorrow again)
  • Is there fluid behind the bolt I've marked up and what seals it e.g washer?
  • Can you pressure the power steering system somehow to check for leaks? Could I seal a hand pump around the reservoir?
59097
 

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M52TU Turbo Swapped MX5
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Hi, so one of the best places for info on power steering racks is the guides on how to depower them

That bolt on the bottom just covers a nut underneath that holds the end of the pinion in place (its not on the newer Mk1 racks or the mk2/mk2.5 racks as its part of the housing) as far as I know there are no seals as such around that nut and I'm fairly certain that there shouldn't be fluid in the part of the housing (there is no way to seal around the teeth on the rack so the seals are further along). If you have fluid leaking from there then it would also be leaking out the end of the rack and leaking out of the rubber gator on that end. The only places it could come from are from the upper part of the pinion that has the flex valve in it or the central part if the seals are gone.

yes the bolt with the locking nut is preload for the pinion

as far as pressure testing the rack, I'm fairly sure the pumps on these spit out around 1000psi+ at about 1500RPM so I don't really think you'll be able to pressurise it without using the PS pump and if you try and pressurise from the reservoir you'll just blow the low pressure lines off.

Is the source definitely that lower nut/bolt? I would expect that the leak is more likely higher up in the valve block and fluid is just dripping down. I'm fairly sure the valve block mates to the lower housing with just an O-ring sealing it so that would be my guess for the source

EDIT: just remembered this is the early rack so its single piece housing and the pinion and valve body is held in by a circlip and sealed with an O-ring at the top of the valve body.

hope that helps
 

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VVT swapped NA & TD04 turbo NB
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Discussion Starter · #3 ·
Is the source definitely that lower nut/bolt?
Thank you this is so helpful, you're an angel.

On first glance all I could understand was that the leak wasn't from the two pipes coming from the pump where they screw in, however I didnt realise there was another join that you've just mentioned between the rack and those two pipes. I will take another look later, clean it up and check again.

Is there any way of running the pump up without turning the wheels? trying to work out if there's a way I can watch for leaks whilst being under the car..

EDIT: I think you are suggesting that one of these 3 are leaking? This is the bit I thought was bone dry
59098
 

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Discussion Starter · #4 · (Edited)
OK further to my previous reply, it looks like its one of the smaller two pipes coming off the rack back to the pump, I didnt realise they were there. EDIT: Ok even more closer inspection, see pictures below, I have found the leak, but where the hell do you buy these pipes new?

Green one is likely leaking, possibly both
59101


They connect a short distance away back to the rack in the middle here:
59102
 

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On first glance all I could understand was that the leak wasn't from the two pipes coming from the pump where they screw in, however I didnt realise there was another join that you've just mentioned between the rack and those two pipes. I will take another look later, clean it up and check again.
The rack on your car is the older design so the whole pinion housing is a single piece so it would either be leaking from one of the pipes or from the very top of the pinion housing. Only the newer racks are 2 piece pinion housings

As far as I know the only 2 lines from the rack to the pump are feed and return, the feed is the one that will have crimped rubber flex sections on it and the return in the one that just has push on rubber hose. The smaller pipes that link the pinion housing to the rack move the fluid when you turn the wheel

With the car on a lift yes I believe you can get to all of the pipes but a couple of them are still a bit tricky. On the floor with jack stands it should still be possible but it will not be a fun job.

the pump should constantly flow fluid around the feed and return lines but it only feeds into the rack when the wheels are turned. This is also the only time the pressure really builds up in the lines (when there is resistance)

This picture looks like a later model rack and on that the top half of the housing (the bit with the 3 holes where the arrow is) unbolts on and pulls off exposing the pinion and valve body.
 

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Discussion Starter · #6 ·
The rack on your car is the older design so the whole pinion housing is a single piece so it would either be leaking from one of the pipes or from the very top of the pinion housing. Only the newer racks are 2 piece pinion housings

As far as I know the only 2 lines from the rack to the pump are feed and return, the feed is the one that will have crimped rubber flex sections on it and the return in the one that just has push on rubber hose. The smaller pipes that link the pinion housing to the rack move the fluid when you turn the wheel

With the car on a lift yes I believe you can get to all of the pipes but a couple of them are still a bit tricky. On the floor with jack stands it should still be possible but it will not be a fun job.

the pump should constantly flow fluid around the feed and return lines but it only feeds into the rack when the wheels are turned. This is also the only time the pressure really builds up in the lines (when there is resistance)


This picture looks like a later model rack and on that the top half of the housing (the bit with the 3 holes where the arrow is) unbolts on and pulls off exposing the pinion and valve body.
Yes some hours of searching have revealed that the reason I'm confused is because no where stocks the lines I need :ROFLMAO: I have emailed Mazda for a price on those two smaller lines. It's definitely one of those two small lines so that's a bit of relief I suppose.
Dropping the rack down doesn't look like it's too much of a job after all.
 

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Discussion Starter · #10 ·
Well I am officially out of ideas and would really appreciate some advice and sanity checkpoint

Got the rack off the car, the only joint on the rack that appears to have any new traces of fluid on it is the area shown in the attached screenshot of a video below that I took before removing the rack.

59107


I got the rack off the car and removed the two pipes pictured above, they look perfect, if you told me they were brand new I'd probably believe you. All the zinc coating looks perfect, the end of the flare looks clean and not pitted.
59109


The bits at the end are grit, not rust:
59110


You can see the high pressure and low pressure pipes below, as you will see there are no traces of fluid from above the the smaller rack pipes
59108


Could fluid leak from the area where the steering rod from the column goes into the rack? Is this serviceable?

I'm considering sending the rack off to a steering rack refurb company and also having the two smaller pipes replaced as a matter of course as mentioned in the above comments, I've already emailed a company to ask for a price for the two pipes.

Thoughts? Any first had experiences with companies that offer steering rack refurbishment?

Send help
 

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Discussion Starter · #12 ·
Is it seeping around the threads on the tube nut, put some PTFE tape on the joint and try again
Almost definitely seeping from there, because it's a flared end, it shouldn't be reaching the threads but I will try anyway as I've nothing to lose.

Currently waiting for a reply from a power steering rack refurb company to see if they pressure test the system after refurbing as this might be the easiest definite fix...

I have cleaned up the threads and reassembled in the mean time, just need to fit back to car and test.
 

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Discussion Starter · #13 ·
After cleaning the rack up, I've put it back together and connected it all back to the car.

Just need to get some Dexron II fluid now but waiting until after work.

Rang Motor Parts Direct yesterday, they aren't doing Mazda racks at the moment as apparently there's a shortage of seals available. I've had no reply from the eBay seller that sell only refurbed racks and I also had no reply from Pirtek.

No one wants my business.

Currently the only two options for replacement I have (if I need it) is a brand new one, which is never happening, or a used known good one.
 
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