My 28 model A sedan came with a round 6 inch dropped axle, spring behind the axle and it was poorly set up with cowl steering. I have very little room with the 427 BBC engine and I'd like to go with cross steering, vega box will probably be used. It has the flat steel steering arms set up for heim joints, drag link was in the front. I'm thinking the spring behind the axle is going to present a problem, I'll need new steering arms. I really wish the axle was a 2 or 4 inch drop but I hate to replace everything due to cost. What is the best way to go about this? I'd like to do it one time, everything else on this car was half a$$ed, it's done cost me more than I planned. Front shocks were never installed on it either.
It will be help if you can post photos, but off the top of my head I’d suggest looking into deep drop steering arms. Not only might you gain some clearance but you can also use Ford tie rod ends with the forged arms.
Heim joints **** on the street How was the cowl steering set up, some setups are good, most not so much. Steering in front of the axle has its issues as well Sounds like bad parts and bad engineering Post some detailed pics and we can answer better as to an attack plan. We are a visual people here !
The parts aren't really bad, the engineering was terrible. It also has the hair pins on it which add to the mix. It had a gear box I never seen before, the steering wheel would turn a quarter of a turn before the tires moved and the box was held on with 1 7/16 bolt, although they did use a grade 8.
I'd start with deep drop arms to the rear, with real tie rod ends. Hook that up and see how much better it is. Lots of steering issues could also be caused by geometry of the wheel offset as well. A brake kit that offsets them outward too much, or wider wheels than stock will be problems. The kingpin is supposed to point straight down at the center of the tire patch where it meets the pavement. What did you previous wheels/tires look like?
It looks to me like you have way too much forward castor on your axle. I am shooting from the hip here but just going by your pic's, I just can not see how you could possibly achieve anything close to correct castor with what you have...
Having ‘49-‘54 Chevy spindles makes things a bit more difficult because I don’t think anybody makes dropped arms for them. You might consider buying 7* bungs and welding them on your present arms so that you could use Ford rod ends. It’s hard to say looking at the pictures, could you fit a dropped tie rod in there? For a tie rod I’d use 7/8 x .125 wall DOM, then you can thread for the 11/16-18 rod ends. The caster does look like it could be at zero or even a few degrees negative but that can be adjusted. With hairpins you can screw the lower clevis out (it appears to be wound in a lot with no thread in front of the jam nut) but you will need to trim the length of the upper tube to screw that clevis in to get positive caster. Loosen the nuts holding the spring perches when you adjust the caster so you don’t bind the spring. BTW, looks like an aftermarket aluminum block. Nice piece, are you going to use that?
You're gonna hate my guts.......either change the axle to an I beam or ditch the hairpins for four bars, absolutely nothing wrong with heim joints for steering ends, buy the best quality you can get and they'll last. The box you have looks like a reversed corvair, looks like it may work, but will probably interfere with headers. You don't have cowl steering, it is set up with a drag link paralell with the frame, acceptable provided you use the appropriate parts to go with it. Do some research right here on the hamb about tube axles and hairpins, how to set caster, and how to make it steer and handle like it should. You got a good start, just a poor mix of parts, with the right parts, your model a should drive pretty nice and not scare you, education is a good thing.
I've got to agree with Trollst on a couple of points. First the hairpins don't work all that well with a tube axle is well known thing even though a lot of rods run them. The issue is that that setup tends to bind when you go over any uneven terrain. You might not notice it but it puts added stress on the pieces. Also as he said, that isn't "cowl" steering and it does appear to be a pretty much standard T bucket style setup although poorly done. I'd also agree with the comment on the negative caster on the axle. It is tilted to negative (front) now more than you want it tilted to the back(positive caster) when you are done. It may be that while it is hanging down it swivels forward but I'd still say your caster is way off from the desired setting of somewhere between 4 and 8 degrees positive so it will track and the wheel will return to center. That along with only one bolt holding the box and maybe some loose rod ends and you have some really wonky steering.
What criteria are you using to make the claim that heim joints **** on the street , ? I have 50k miles on my heim joints , all street miles ...
What I’ve read and experienced personally, that MOST heim joints are not made to be used on the street and subjected to the abuse of regular roads. I know you can buy quality heim joints as well, but most don’t seem to last or give the quality that is expected out of them in street driving. It was a blanket statement and not 100% accurate but in most cases stands true. Your mileage may vary on this statement
You said drag link in front did you mean tie rod? Most front tie rod setups have terrible ackerman. When you use steering arms meant for rear tie-rod in front things are way off. This is correct for front tie-rod https://www.tbucketplans.com/wp-content/uploads/2015/08/ackerman-bending-steering-arms-reversed.jpg I haven't seen a NHRA rule book in years but they did require a large flat washer be used incase of heim joint fail. Keep in mind with split bones you are turning the front axle into one large sway bar and it will effect handling accordingly.
OK, just got back on here. Yes I meant tie rod, seen that after I posted. When ever I use heim joints, I use CM joints and name brand. I got a chance to fool with it a little today. The axle right now is tilted 5 degrees back, I'll shoot for 6 or 7 is what I was thinking anyway. I raised the engine and trans some, it's at 4 degrees and is about as high as I want to go. I can make the corvair box to clear everything by moving it back a little but I can't move it in far enough for the column to line up. I guess I could go with a double U joint. The alum block is junk, I'm using a stock block .030 over 427 BBC. As for the axle and hair pins, I don't like the 6 in drop axle, would rather have a forged and don't really care for the looks of hair pins or the 4 bar set up. All the stuff is new, dirty but new. I don't know what I could get out of everything if I sold it. I think it was 48 in, center to center of king pin, been awhile since I measured it, as for the wheels someone mentioned, it had 15x4 torque thrust with 15x10 on the rear, wheels are new along with tires.
That front axle set up/***embly you have is relatively cheap to buy new. There's nothing cheaper/ I don't think so anyway.
I think I'm going with what I got if I can get the box worked out and next winters project will be changing to a forged axle with split bones. That way I can jerk all of this out and sell it complete. I do appreciate all the help and when I change it I'll need more.
I don’t know Mike, that might not be the best plan. You will be spending money on brakes along with all the other incidentals needed to hook up the steering, shocks and more only to obsolete that stuff and buy new. I vote for either using what is there or selling it now and starting fresh.
I don't know....if you're like most of us, you'll never replace that stuff, do it now so you'll have peace of mind at 60+ mph.
If it's wrong it's wrong. The same guy that used one bolt for the steering box did/designed the rest of it too.
You will spend time and money on something that is not right to begin with. If any of these parts are subpar quality you will always have that “ meh” feeling. Better off pulling the whole ball of wax out sell it off to someone who’s does not care and start from scratch. Sounds like you know what needs to be done and how to accomplish it so just do it! Nothing worse then trying to adapt bad parts and bad engineering it will always be just that.... bad and leaving you not being satisfied with the outcome. I read you already redid and spent more then you anticipated, but if you don’t do it right now, it will always be a compromise and will need to get done right in the future.
It has all new rotors, calipers and everything to put it together. The only thing I'd have to fab is shock brackets for the axle. Before I tore the front end apart, I set the toe in at 1/16. I redone all the rear end mess and narrowed the 9 inch on 1 side to center the pinion. Using a string I I run it from the center of the tie rod end, heim joint, through the center of king pin and back to the center of the pinion and it's really close. An elderly gentlemen, older than me, was at the shop picking up some seats for his model A and he was looking at it and his opinion was it ought to drive really good. He stated that the ackerman was right on it, his words and opinion. The radius rods is the only major thing right now other than I don't like the modern look of the axle. If there is anything that's off or unsafe let me know.
It looks like around $1300 for a forged axle kit with split wish bones from Speedway. That is the axle kit plus the brake kit, 11 inch rotors, pretty much everything but the gear box if I went with cross steer.
No body gives a **** about what I say,,, But here it is anyway Changes in Axles change things like ride height and ch***is rake. start changing those two and a bunch of **** goes out the window.
That's 1 thing I'm worried about also, spring over axle is going to create a bunch of changes, different radius rods 4 bar or whatever will create mounting point and bracket changes. The domino effect.
The tie rod in front gives you reverse Ackerman. Your tires will scrub when turning. When you pull into a show, your wheels will be chirping and everybody in ear range will know it.
Just because the tie rod(s) is out front doesn't mean the ackerman is off , with the proper steering arms ackerman works either way , there's an awful lot of factory frt steer cars out there functioning perfectly .
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