roadster front spring problem

SAJ

SAJ

Well-known member
I have an early RHD 1930 standard roadster, which someone tried to turn into a deluxe in the 1990’s. The front spring it came to me with allowed the draglink to rub on the tie rod and the shackles were grounding on the axle, with some wear evident on all items which touched. The shackles were rubber-bushed. I removed the spring with the intention of re-arcing it cold, but found the measurement between the eyes was already smaller than new specification by a small amount and the arch height was 5-3/4 inch as specified . So I bought a new “premium” roadster spring from Snyders and fitted it with new non-rubber shackles and gaiters, after lubing it with moly disulphide paste (applied as a liquid in Shellite solvent).
This was about 5000 miles ago, and I have since gone through a set of new M&S shocks and now have a set of new Bill Stipe shocks, which seem very nice indeed.
But my ride still seems like the shocks are far too stiff, no matter where I set them.
In looking closely, I see that the shackles just clear the axle, but the left hand one is hard up against the left wishbone fork at rest and the right hand one only just misses.
This means the spring cannot flatten, and my suspension movement is limited. Both shackles still seem too close to the axle to me too – maybe .030 inch clearance underneath, at a guess.
When I fitted the new spring I was surprised that it was the same length between eyes as the old one, and same arch height too, but I assumed the new spring rate would be greater and my old spring had lost stiffness in some way. At the time I was overhauling the whole car before a long rally, so did not pay much more attention to the spring fit.
The rubbing drag link went away when I fitted a shorter pitman arm, before this rally. However, I am now chasing more compliant, less choppy suspension, though I have never ridden in another roadster to compare it.
Can anyone help with advice on what may be wrong, please, or what I can do to regain the lost clearances? I have attached photos showing the clearances from underneath and in front of the car the car. Thanks in advance. SAJ in New Zealand
 

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Defenately not right, You need to do some measuring. The spring shakles should be at a 45 degree angle when loaded. Wrong axle perhaps?
 
SAJ Couple of thoughts. It may have something to do with spring shackle or perch (or a combination). You didn't say if you replaced shackles. So my commnets are based on if you didn't. If you have access to an original shackle measure the center to center dimension & compare it to the the shackles you installed, if installed ones are wider that will lower the spring, also the bolt diameter if you reused them they might have been worn. If not that how much wear was there in the spring perch bushing hole? Any wear could lower the bushing & in turn the spring eye. Were shackles snug in bushings? There is not a lot of clearence between spring & axle to begin with so when you add up wear of different components it dosen't take much to touch. Also urethane bushings will compress some as well. If not any of the above are perch axle to center of perch spring bushing hole height dimensions correct. Axle perch holes ovaled so perches aren't centered on axle? Good luck. Tim
 
On the RH photo,the brake shaft hsg appears to be not far enough into the king pin ball.This suggests that the perch has sagged.You should be able to put your finger between the spring eye & perch & have at least 1/8 to 1/4"under spring to axle.The rust dust under perch makes me think the perch is loose in axle as well.
 
Thanks MN Stumpjumper. The axle seems just like other Model A ones I have seen. Are there different versions of this axle? I thought they were all the same throughout Model A production. If not so that adds an interesting variable.
Tim B. The shackles and pins are new replacements sent with the new spring from Snyders. The Bushings are new too and a tight fit in their housings. Shackes are the same measurements as old ones I have. The old bushings were black rubber that I removed, leaving the perch eyes unworn. Perches are tight in the axle, holes not oval.
I am not sure what your "perch axle to centre of perch spring bushing hole height" means, and my car is not with me now, but I will look at this tomorrow, but I probably need another set up to compare it with.
I will contact Tom Jordan at Snyders and see what he suggests if there are no other obvious things that I may have done or could do, other than re-arching the new spring cold. Does this work as a permanent cure? I see it in Les Andrews' book, but my instinct tells me that re-annealing, resetting and re-hardening/tempering is the real answer. And then only if we have good quality spring steel to start with.
Hopefully someone else may chime in with more experience on my problem.
SAJ in NZ
 
Thanks Columbia. I think you may be right. I have been watching the fretting corrosion coming out of the perch bolt, but the bolt seems very tight in the axle and I could not budge it last time I tried. I guess it must be working in the axle though, from all the rust emerging. This has happened quite suddenly, so who knows what I may find when I dismantle it and have a look. I bought a car when I was a youngster that had its kingpin bushes repaired with epoxy, which was new on the market in the early 60's. After only a few miles the kingpins went from tight to worn out and I sold the car. "Farmers" fixes last a lot longer than that! I hope this is the answer and it is just a matter of restoring the fit in this area . I see, too, that the shock link lies at an angle as BoB C points out
Regards to all who answered. SAJ in NZ
 
SAJ,
Looks like your spring may be a little long..mabe an inch ! Mabe perch bolt holes worn out too, but spring , new or not, looks long. If an inch shorter, then when it is 'spread' , shackles should ...reach out to connect and NOT go back against perches when spreader removed and car weight put on ?
 
Something's wrong, and I'm guessing it's not the spring. You have two now with the same dimensions and the same problem. I put a new Snyder's spring on my roadster a few years ago, and it works fine. It seems crazy, but I wonder if your Perches are bent. Maybe someones idea of how to lower the car.
 
I have re-arched springs cold.I take them apart & set one leaf at a time on edge on the concrete floor & draw the curvature of the leaf on the floor.Then take a short piece of 5 or 6 "channel iron & working the leaf back & forth across the upturned sides of the channel,beat on it with a 4 LB hammer.Check every so often until the curve is 1" to1 1/2" taller.The short leaves dont need to be done as much.Ive had good luck doing front springs this way.
 
Many thanks to you all. Tomorrow I will see if the perches come out easily and report what I find. Hardtimes, the old spring was 30-3/16 inches between the centres of the shackle pins (i.e bush eyes) when removed from the car and the arch was 5-19/32 high to the bottom. I recorded the new spring as the same at the time, before fitting it. This length is what Les Andrews specifies as correct in his book.
I will explore Geo H's idea, but I reckon the axle holes are flogged out. Columbia's 1 to 1-1/2 inch is helpful too. If I re-curve them this is a good guide.
Thank you all very much for your replies and advice.
Regards
SAJ from NZ
 
SAJ said:
Many thanks to you all. Tomorrow I will see if the perches come out easily and report what I find. Hardtimes, the old spring was 30-3/16 inches between the centres of the shackle pins (i.e bush eyes) when removed from the car and the arch was 5-19/32 high to the bottom. I recorded the new spring as the same at the time, before fitting it. This length is what Les Andrews specifies as correct in his book.
I will explore Geo H's idea, but I reckon the axle holes are flogged out. Columbia's 1 to 1-1/2 inch is helpful too. If I re-curve them this is a good guide.
Thank you all very much for your replies and advice.
Regards
SAJ from NZ
Click to expand...

SAJ,
Well, by process of elimination, i.e.- you've replaced spring/shackles/bushings and state that perches are OK.
Now that leaves the condition of the axle (bent/not) and the spring.
Yes, I say the SPRING because...it wouldn't be the first defective repro part that is not correctly made (arched) for the application.
At this point, I'd be focusing on the axle for proper shape !
 
I'm thinking the same as Jim in post #12.

SAJ, what is that bolt in the front crossmember? Maybe a bolt for some repro front motor mount?
 
Something is wrong with that spring, the shackles should be more horizontal. The way is now the axle can pendul-ate causing weird steering control. I've done a few springs from Snyder's and they were fine but they were not exact repro, more like driver replacement.
Did you try to communicate with Snyder's?
GW
 
I dont know if current repop perches are any better,but back in the 70,s they were made of cast iron & were thicker looking than the original forged steel ones.They would bend easier than the originals.I dont think the repop perches & shackles would have stood up to the pounding they had to endure on the washboard roads of the day.Even in the 50,s there was very little pavement in our area.As for the perch,just because the nut is tight doesnt mean its not loose.On my car I could not tighten or loosen the nut even with heat,so I had to carefully slice off both sides of the nut & knock off the other 2 sides with hammer & chisel,& the threads were OK.There was a slight space between axle & RR,so I notched a couple king pin shims to slip in place & used a new nut with some anti-sieze & sucked it up tight. Another problem you might have with the brake shaft hsg not in far enough,is that the push rod for the brake wedge may bind or bend inside the KP & make that brake slow to release.
 
Thanks for all the helpful info. I removed both perches today. They came out with a bit of a tap and wiggling. There was rust on them and some bright marks on the top tapers, but they were not really loose. A few thou wiggle when just held down by hand but none I could induce with levers etc when cinched up tight again without the shackle in place. I think they are OK and, even though the nuts were really tight (probably 120 ft-lbs at least), I think that was corrosion and they will go up much more snug when I clean lubricate and refit them.
The “new” spring, whilst still clamped with the centre U bolts has 5-1/8 arch and 31-3/8 between eye centres. This is on the outer (loose) limits of the specs I have. The old spring is tighter with 5-3/8 and 30-13/16 inches. Maybe the centre U bolt is flattening the new spring a bit. I will see when I remove it.
Moving on to the axle question, in elevation it has 2 inches drop at the centre, measured from the ends, excluding the small bosses the kingpins fit on top of.
If this is bent it would cause the perches to lean in as suggested.
I am not sure which distance to measure across the perches, but I have 37.2 inches across the bolt centres at the bottom – agreeing closely with Roundvalley
The distance across the perch shackle eyes seems more significant and I have 33.94 inches, with the shackles out (i.e. no spring tension). I will reinstall the shackles and spring tomorrow and measure distances with load on the perches both inwards and outwards and see if they move, but I doubt it. That is, with axle hanging from the spring and wheels off the ground, and the reverse, car body fully loaded and supported on the springs.
That leaves a weak or too-long spring, bent perches, over-bowed axle or… what else?
I wonder if the perches ARE too deep into the wishbone yokes, which is what Jim and Tom suggested – if they have chewed their way into the tapers with fretting corrosion over a long period of time?. There are several spare threads at the bottoms under the nuts and more on one side than the other. I will check in the morning. If so I can turn up hardened tapered spacers to fix this, but the brake shaft housings will then be a little out of line, I suspect.
Columbia, my perches are both forged not cast.
Tom , some bolts are rivet replacements because the cross member has been in an accident at some time and refitted with 5/16 bolts. The more central one is indeed an aftermarket bonded rubber engine mount the car came to me with. I have the proper forged mount and new springs and will fit them while the front is off to see if it improves vibration on the overrun.
Thanks a million again guys. I may have several things adding up to the problem as suggested I think.
SAJ in NZ
 
Someone needs to post a picture of a good setup. Unfortunately I don't have a picture and can't take one off my worn temporary front end.
 
Is there another axle handy or a set of perches nearby that you can compare yours with?? It looks/sounds like your perches are sitting too "low" in the axle, or your axle is bent down in the middle although your measurement for perch spacing appears correct.
Paul in CT
 
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