Manual Steering Rack Source - Issue Found

[CFranks]

Hi All,

My car just failed it's annual state inspection and i'm REALLY glad it did, my FFR manual rack was minutes away from full failure. Still unsure exactly what happened, but metal pieces were falling out from inside and the inner tie rod was incredibly wobbly and loose. I'll post pictures and an assessment once I get it out. I am now looking for a replacement as I'm sidelined until I fix it. Are there any recommendations for a good replacement part and source? I would call FFR and just order the same part, but given this happened i'm now a little nervous (I only have 1100 gelcoat miles on the car - kit is a MK4 delivered in 2013).

I have EPAS power steering so want to stay with a manual rack.

Any recommendations? Go with FFR or elsewhere?

Thanks,
Craig

[Hoooper]

Not sure when they switched to unisteer but the current racks are provided by unisteer which is a pretty reputable steering rack company. You could buy a rack from flaming river or various other suppliers but then you would need to pull the inner tie rods and install the spacers that are already installed in the FFR rack to get the pivot location correct. Id first take a closer look and see what parts were failing in your current rack

[RoadRacer]

I'd certainly call FFR and tell them what happened (they may see this here anyway). This seems an unusual failure.

[rich grsc]

I'm going to do a WAG and say maybe the EPAS over stressed the rack?

[Hoooper]

I'm going to do a WAG and say maybe the EPAS over stressed the rack?

My thought as well, which is why I would start by doing a little investigation.

OP, do you have solid rack mount bushings?

[CFranks]

My thought as well, which is why I would start by doing a little investigation.

OP, do you have solid rack mount bushings?

I have the polyurethane mounts that came with the kit. I suppose it could be EPAS (although i'm not sure how?), which would be very concerning as there are many of us running around with this setup. The symptom was you could grab the front PS wheel and turn it in and out much more than normal, when looking at the rack you could see the inner tie rod pulling in/out with it. On investigation in pulling back the boot, some metal bits fell out and there seemed to be nothing holding the inner tie rod in place inside the tube. The car unfortunately is still at the inspection shop so I can't go take a look or send better photos, I go fairly far away to a shop I trust so it made more sense to leave it there vs. have it towed back to my place. My plan currently is to install a new rack and not mess around with trying to fix this one, although the root cause analysis being discussed here is very important so it doesn't happen again.

[rich grsc]

I doubt you could get parts for a repair, but understanding what happened is important. It could have just been a bad one.

[Walt]

Craig, i would like to know what you find out , im running the same setup, i think the rack i got in 2014 . I dont know what brand it is. I got it from FFR.
Walt

[toadster]

check the classifieds! I sold my manual rack a few months back, they pop up once in a while ;)

[GoDadGo]

My kit was built in 2015 and the steering rack came from Unisteer but I don't see a Factory Five listing on their website.

My assumption it is one of their Mustang Racks, but I don't know which one.

https://www.unisteer.com/collections/rack-pinions

I'd call Tony or Dan at Factory Five because those guys seem to know everything.

[Hoooper]

My kit was built in 2015 and the steering rack came from Unisteer but I don't see a Factory Five listing on their website.

My assumption it is one of their Mustang Racks, but I don't know which one.

https://www.unisteer.com/collections/rack-pinions

I'd call Tony or Dan at Factory Five because those guys seem to know everything.

The rack is a unisteer part # that they dont publish for sale, it seems to be a mustang rack with spacers on the rack to space out the inner tie rods. The number is 8001070 but you wont find that # anywhere for sale new from unisteer, presumably an agreement they have with FFR. They can be found new on ebay, parts classifieds here, FFR builder social media groups though as I just bought one recently and there were a number of people who had them to offload when asked.

[mike223]

I'm going to do a WAG and say maybe the EPAS over stressed the rack?

Not likely.

The driven gear teeth inside the EPAS are polymer and the controller is programmed not to overpower the polymer.

You would wreck the EPAS before you could wreck the rack - meaning you would lose power assist, but you would still have manual input on the rack.


The driven gear resembles this:


133940


The shaft going through the (driven) gear would stay intact (so even if you lost power assist you still have steering input).

[Rdone585]

Would it be an option to send the whole rack to unisteer, with an explanation of what has happened, since it's basically a new rack? Perhaps ask FFR their thoughts on doing that. Unisteer may be as interested as we are to see what actually happened. They might even repair it and send it back to you. Many of the better vendors will do this as it helps to keep customers engaged purchasing their products.

[Hoooper]

Not likely.

The driven gear teeth inside the EPAS are polymer and the controller is programmed not to overpower the polymer.

You would wreck the EPAS before you could wreck the rack - meaning you would lose power assist, but you would still have manual input on the rack.


The driven gear resembles this:


133940


The shaft going through the (driven) gear would stay intact (so even if you lost power assist you still have steering input).

The EPAS gives additional mechanical assistance to your given input, right? In other words, the total force on the rack would always be your input force + the EPAS force? In which case even if the EPAS can only give an additional 20lbs of force it would still be 20lbs of force more than you could put on with manual steering.

[CFranks]

Craig, i would like to know what you find out , im running the same setup, i think the rack i got in 2014 . I dont know what brand it is. I got it from FFR.
Walt

Will do. As soon as I get the rack off i'll post some pictures and anything I learned about the damage.

[mike223]

The EPAS gives additional mechanical assistance to your given input, right? In other words, the total force on the rack would always be your input force + the EPAS force? In which case even if the EPAS can only give an additional 20lbs of force it would still be 20lbs of force more than you could put on with manual steering.

Yes.

Your steering input is straight through.

There is a torque sensor built in - the controller senses your input (torque) and applies power to the assist motor based on whatever "map" the controller is operating with.

On many of the commonly adapted OEM applications, the EPAS needs to get a signal off a communications bus telling it what model of car it is in + vehicle speed (mapped assist).

The little black boxes sold off ebay provide this signal, and adjust the speed signal off a manually adjustable potentiometer (variable assist).

More advanced little black boxes can adjust the speed signal (bits + bytes of data on a serial communications bus) off your transmission speed signal if desired (a few extra $, complications, and potential failure modes).


Another complication is the more stuff you get between the steering wheel and the torque sensor (at the EPAS) - the torque sensor reads any resistance as steering input - sometimes noticeable as not self straightening the steering wheel coming out of a corner.


Here's how I did mine (and the location is much better IMHO): https://thefactoryfiveforum.com/showthread.php?28241-Mk-4-Pull-A-Part-EPAS

[CFranks]

Hello all. Wanted to give an update on what I’ve found to close this off. I was able to source a new FFR manual rack (thanks Mark D!) and swapped it out for the broken one. All is well now and I’m back on the road. In comparing the two, there are two fundamental items that were damaged/missing from my old rack. 1) The standard FFR manual rack includes 2 limiters (a black rubber one and a white one) to limit the rack travel from stock. Both of these were missing from my rack. You can see the new rack below and my damaged one below. 2) This is the real issue, inside the tube I believe there is supposed to be some type of bushing. That bushing was completely blown away. As a result, the rack was flapping around inside the tube, which is the source of my wheel wobble. I tried to post a video below, not sure if that works on Flickr. There appears to be chunks of metal/rubber along the walls in the grease.

I honestly have no idea how this happened unfortunately. Most folks who know EPAS don’t think it would do this. So I may just be left with a defective rack, or maybe the original owner (I bought this as an unfinished build) did something that caused issues inside the rack. I’m going to monitor closely every few weeks to see if it comes back in case this issue is somehow related to my setup.


New Rack

https://live.staticflickr.com/65535/50277646508_bfed9ddb0b_k.jpg (https://flic.kr/p/2jAS5Eh)



Damaged Rack

https://live.staticflickr.com/65535/50278320031_bd5fb61a82_k.jpg (https://flic.kr/p/2jAVwSK)



Wobble Video

https://live.staticflickr.com/31337/50278319821_0b8be76e3a_b.jpg (https://flic.kr/p/2jAVwP8)

[Walt]

Oh man Craig, are the parts missing on that side on the other side? Glad you have it taken care of!
Walt

[gtrclark]

Sorry to bump an old thread, but did you happen to notice a big loss in turning radius going to the rack with the black and white limiters? How many turns lock to lock is it?

Thanks,
Mike

[michael everson]

I had the same failure on a couple of these racks. I doubt they ae Unisteer. Chinese knockoffs. The bushing that supports that side of the rack was completely destroyed. It almost seems as if the bushing and grease are not compatible. I made up a bronze bushing and pressed it in. That fixed it.
Mike