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Massive Intermittent Dead Spot In Steering

No Crust Racing
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No Crust Racing Grand Master

No Crust Racing

Posted
Posted

Hi guys,

At the last DECA I was giving the car a workout and found that the steering developed an intermittent dead spot in the centre. I had the passenger grab the wheel at one stage to prove I wasn't going crazy.

The car is an S13, CA, and I'd assume it's the original rack, it certainly doesn't look reco'd. I'm assuming rack as the tie rod ends looked fine, no bends, threads are good, no free play that I can easily get to happen up on stands. Rack mounts and bushes "look" OK to me but I'm no steering specialist. I topped up the power steering reservoir and thought it got better but then it came back, it seem to be when loading the car up hard side to side on the skid pan, which to me implied a hydraulic issue in the rack. The boots on the end of the rack aren't filled with fluid so I'd say the seals at the end of the rack are good, no leaks that I can see.

At it's worst there's probably a good 20-25 degrees dead space in each direction from centre.

I had 235 semi's on it at the time, -2.5 deg camber. Can't recall toe/castor settings right now.

Thoughts?

DVS JEZ Grand Master

DVS JEZ

Posted
Posted

you need to determine where the freeplay is exactly. jack it up and get some one to turn the wheel in the freeplay back and forth and check everything,

what colour is the powersteer fluid? is it burnt?

No Crust Racing Grand Master

No Crust Racing

Posted
  • Author
Posted

It's on stands at the moment and I'll be doing that but when it was intermittent and seemed relative to lateral load on the car durnig cornering.

Fluid is standard colour, didn't look any different to what came out of the bottle when I topped it up and didn't smell burnt.

I'll be getting under it in the next few days.

No Crust Racing Grand Master

No Crust Racing

Posted
  • Author
Posted

OK here's what I found.

Car up on stands, me lying on my bak with the leadlight, GF turning the wheel.

Mechanically I can't see any free play, I had the GF do fast and slow turns full lock in both directions with and without me providing enough resistence on the wheels to stop her being able to turn the wheel in the cabin.

I also had her hold the wheel hard while I tried to make each wheel turn, no freeplay there.

What I did find is that one rack boot has a split in it and inside I can see brown grease. Without cmoparing to the other one I'm not sure if it should be that colour or not. If it shouldn't be covered in crud then I suspect that when the rack has a lot of pressure on it there may be fluid getting past the outer seal and into the boot, however the boot didn't show signs of large amounts of fluid - maybe early days for the leak.

I also noted that the inner part of the tie rod where it joins the rack has been bent back, I'd say from hitting the rack on full lock turns too hard.

I also note that the outer tie rod ends/pins that connect to the wheel hub assembly have split boots on both sides. I'm a bit vague on terminology, sorry.

Thougths? Mechanically it looks and feels ok. A mate was telling me there's a valve where the steering column knuckle joins the top of the rack and they are common failure points just for something extra to consider.

Thanks so far guys :D

Japanese.Motorsport Contributor

Japanese.Motorsport

Posted
Posted

A bent rack end will cause that, as it spins around it can play havok, but unlikey due to your diagnosis.

If you don't know how to diagnose problems its hard to rule anything out.

There are only a few links in the steering (5 if you count the rack bushes)

Jack it up, grab the wheel at 3 and 9 o clock. Keep steering the tyre back and forth by hand, If you feel any freeplay, your getting somewhere. Get a mate to do the same while you watch closley at each steering part to see whats got free play.

To me it sounds like the rack is stuffed, Ive never heard of the gears loosing a tooth, but it might be possible.

Could also be a caster rod bush/bearing gone, it might be binding the steering.

To test your rack bushes put it on the ground, get 5 fat mates to sit in the engine bay, then you get under the car and watch the rack while your girlfriend steers left to right throughout its whole range.

5mm of movement is normal, any more or abnormal movement is a bad sign, as under load with semis the problem compunds.

Really its impossible to diagnose over the internet.

No Crust Racing Grand Master

No Crust Racing

Posted
  • Author
Posted (edited)

This leads me to believe the outer seal in the rack is weeping under pressure? I assume this requires a rebuild?

Bad side

post-23873-1283656656_thumb.jpg

Good side

post-23873-1283656694_thumb.jpg

Edited by ActionDan
T04GTR Grand Master

T04GTR

Posted
Posted

also, check the drivers side rack bush. it is usually covered in oil and perished. with the car on the ground jiggle the steering wheel. you will be able to see the rack move side to side if it is worn.. this can feel like freeplay when driving.

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