Bump steer - or maybe lean steer problem?

RyanG

RyanG

True Classic
Hey everyone - I have a handling question that I’m hoping others may have some insight into. I’ve had my x1/9 about 9 months. It’s a 1982 FI car. Fairly solid. I’ve posted some things on it previously. In the last 9 months I’ve done work to get it running reliably and I’ve refurbished brakes and suspension.
Specifically regarding the suspension I replaced all bushings with poly bushings from Vicks. All ball joint boots replaced and all of the ball joints feel solid. New Michelin Exaltos (really like them) and recently the car was aligned. Also, it appears to have the grey replacement KYB gas struts. I did cut about 3/4 of a coil off the fron springs to get a little more nose down stance. Car sits pretty level now.
Here’s my issue. When driving more spiritedly, on sharper corners, about mid corner the car will suddenly turn in a bit dramatically. Kind of like it suddenly really hooks up. I was experiencing this after I did all the suspension work but before it was aligned and thought it was an alignment issue. When I got it aligned the front toe was quite a bit off. That is now fixed and it still behaves the same way. Under other driving conditions it tracks straight, brakes straight, feels solid and behaves great. I only have a rudimentary understanding of bump steer. Could this be a bump steer issue, could it be the suspension geometry changing when the car gets to a certain amount of lean (why it happens about mid corner)? It acts the same way in left or right corners. It doesn’t act funny going over bumps in a straight line. One thing I haven’t changed out are the top shock mounts. But they don’t seem terribly worn. Also, it feels like this is happening at the front and not a symptom from the rear but I don’t know for sure. Anyone with similar experience or advice? It can be a little unsettling in high speed corners when the car suddenly wants to turn into the ditch. Thanks in advance for anyone’s thoughts.
 
Something is worn.

At the top of the strut thre is a bakelite bush, this is for the pivotig action so the car steers, sounds like perhaps these are broken or maybe missing from both sides up front...I think you're feeling a toe / camber change related to the upper pivot point moving....either that or both lower ball joints up front are worn / inner control arm bushes are worn and something is moving under cornering loads.

SteveC
 
RyanG said:
It can be a little unsettling in high speed corners when the car suddenly wants to turn into the ditch.
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My first thought is "Stop driving at high speed into turns until this is resolved!".

I had a Fiat buddy here in the STL that had a similar issue, but he kept driving the car hard till it did go out of control. Fortunately, he was fine, the X not so much. Check you rear lower control arms, if those ball joints are bad, they can produce a steering effect. I drove my buddy's car after the frame damage was repaired and it was still acting weird. travelling in a straight line, the car would " rear steer" with any acceleration change. It was scary. After poking around we found that the right rear control are ball joint had play it it that allowed the wheel to turn when it should be traveling straight. No bueno! Got a replacement from MWB and the problem was resolved.

I know you had an alignment and you have checked the ball joints, but take another look. My buddy's car was aligned twice before we found the actual problem.
 
We’ll - high speed is relative. It’s just strange because it’s pretty predictable and consistent. And the car doesn’t act strange any other time. In general it feels really solid.
 
fiatfactory said:
Something is worn.

At the top of the strut thre is a bakelite bush, this is for the pivotig action so the car steers, sounds like perhaps these are broken or maybe missing from both sides up front...I think you're feeling a toe / camber change related to the upper pivot point moving....either that or both lower ball joints up front are worn / inner control arm bushes are worn and something is moving under cornering loads.

SteveC
Click to expand...
I suspected this might be the case. I will have to take a look at these. Thanks
 
If the rear ball joints are worn you can really tell somethng isnt right at the rear of the car... to test ball joints front or rear lift the car, and insert a lever / really big screwdriver between the upper side of the ball joint and the hub, move the lever up and down, there should be zero movement at the ball joint, if it moves then the joint is worn and needs replacing.

SteveC
 
RyanG said:
www.midwest-bayless.com

Steering Pivot Thrust Plate Bearing PAIR 2x (Fiat Bertone X19, 128 All) - NEW

Steering Pivot Thrust Plate Bearing PAIR 2x (Fiat Bertone X19, 128 All) - NEW
www.midwest-bayless.com www.midwest-bayless.com
Are these the parts you’re referring to?
Click to expand...
well they are a replacement item that converts the plain bakelite bush to a radial bearing.

the standard part looks like this.
www.ebay.com.au

Fiat X19 X1/9 128 127 upper strut pivot bushing 4188713 (each) | eBay

Find many great new & used options and get the best deals for Fiat X19 X1/9 128 127 upper strut pivot bushing 4188713 (each) at the best online prices at eBay!
www.ebay.com.au

SteveC
 
RyanG said:
Gene - why the passenger side? I suppose I should just replace both of them? Initially I didn’t when I was doing all the work because they looked pretty good.
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Passenger side apparently takes more of a beating than the driver side. My 128s and the X rack in my 600 have all had problems on the passenger side.
I've never had to disassemble a rack so I'm not sure exactly whats over there but I've done several passenger side bushings. May not be your problem but it's worth checking.
 
gene cooley said:
Passenger side apparently takes more of a beating than the driver side. My 128s and the X rack in my 600 have all had problems on the passenger side.
I've never had to disassemble a rack so I'm not sure exactly whats over there but I've done several passenger side bushings. May not be your problem but it's worth checking.
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Thanks
 
I have had several Xs with busted/missing steering rack bushing and it always caused a clunking sound but didn't create hazardous cornering.
 
only the passnger side has a nylon bush internally for the rack to slide thru / support, but thats usually accompanied by a clank / clunk from te passenger side if that wheel hits road irregularities.

before buying a bunch of parts you really need to determine what is worn.

I've seen strange thngs like strut inserts where the large gland nut had come loose and the top of the insert was moving in the housing.
One X19 ace car I helped rebuild had been spherically bushed on the inner lower control arm, and then they had used a 1/2 inch bolt in this position... normally it's an M10 and the bodywork had been drilled out to accommodate the larger fastener, but somewhere along the line the bolt must have been left loose, or they drilled the hole too large in te first place as the hole in the bodywork had become slotted out... it gave the wierdest feeling when you turned in as the lower pivot point was shifting a mm or two! to fix that required welding some washers either side to fix the hole in the body.

so you need to get under the car, while someone else rocks the steering back and forth a 1/4 turn and look carefully for any signs of worn out parts... and test ball joints / tie rod ends to make sure they are not worn out too.... this is easiest to do on an inspection pit where the wheels are on the ground and loaded with the vehicle weight

just because the wheel alignment guy didnt pick it up doesn't mean it's not worn, I've seen countless poor alignments in my 40 years as a motor mechanic.

SteveC
 
Hi Ryan.

RyanG said:
Gene - why the passenger side? I suppose I should just replace both of them? Initially I didn’t when I was doing all the work because they looked pretty good.
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Because....only the passenger side of the steering rack has a bushing !!! and yes...check it for play. Crawl under and grab the inner tie rod end and see if you detect any up and down play in the bushing...

Another possibility in your case might be those poly bushings you installed in the inner end of the control arm. Look at this thread from a member finding the same symptoms as you after installing the same poly bushing kit 😭 At least worth checking.........

Spooky handling...found my issue

Last year I replaced the worn out bushings in the front suspension with some urethane ones when I replace my old and busted shocks. I assumed that the wierd handling was a result of the suspension being out of alignment. There was no excess movement or the hub, wheel bearings seemed ok too...
xwebforums.com

Good luck. Doug
 
Thanks folks. I read through the “spooky handling” thread and looks like I have a little sleuthing to do. I do have the poly front bushings so I’ll start looking there as well as ball joints. I don’t remember if this issue started after I replaced the bushings or was there before as well. Before I did suspension work I had t driven the car very hard since it had old tires on it and it was still new to me.
 
Little update - this afternoon I got the car off the ground and did some looking around. In general everything seems pretty tight. The steering rack bushings I think are fine (although dirty and the rack may need some attention to clean up a leak)
982FB8EC-AC56-4887-A74E-6B4260577DD5.jpeg

49BBC98F-4B70-4326-83BD-5A7A52AC7E75.jpeg

all the ball joints front and rear feel solid. I feel no play in any of them.
However I did fine this -
D7A31F22-40D2-400C-A28C-1A921A9EBE9B.jpeg

this bushing doesn’t look happy. Also, when I turned the steering wheel back and forth there is some movement of the arm at this mounting point. I’m also able to move the arm back and forth a bit just by grabbing it and yanking. There is maybe an eighth inch play. I imagine under load that could possibly be a bit more. As it turns out I have a set of new stock bushings that came with the suspension rebuild kit I got from rx1900 (thanks Doug). So my plan is to swap out the poly and put in the stock bushings
5485BCF5-CF51-4474-99ED-0E9660199CF0.jpeg

I’ve taken the passenger side a-arm off and also noticed that the steel bushing insert on the poly set has a slightly larger ID and the bolt is a bit sloppy. This is similar to what was described in the “spooky handling” thread. Anyway, I’m hoping this will solve the problem. If not I’ll look at the strut pivot bearing.
Does anyone have a magic trick for pressing in the stock rubber bushing? It’s proving to be tricky.
 
These have 500 or less miles on them. Perhaps I installed them wrong? But not sure how I could have. Not convinced these are good value for the money.
D502AA24-B0A3-4B06-8770-3278BE225E67.jpeg
 
I think you are on the right track. The damage shown is normally the result of too small a diameter bolt that allows the bushing insert to "slide" or cock to one side inside the mount. You mention the new poly bushing bushing was larger. What did the bolt/bushing fit look like when you originally removed the arm to install the poly set? Was the original rubber damaged in a similar way? Sometimes over decades of dreaded POs, many hardware items unfortunately get replaced with whatever is handy. Any play you can find by laying hands on it is multiplied many times under driving conditions, so if anything moves during reassembly, rest assured it will really move when underway.
 
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