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| May have discovered partial cause of caster problem https://www.slantsix.org/forum/viewtopic.php?t=43350 |
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| Author: | wjajr [ Sun Jan 23, 2011 9:40 am ] |
| Post subject: | May have discovered partial cause of caster problem |
The first alignment after purchasing the Dart, the left side caster = -6*, right = -3*. Installed offset bushings corrected caster on left side = -1*, right side +1*. This did not please me, car still handled poorly, installed CAP tubular UCA that provided + 9* adjustment. My less than savvy front end guy struggled to dial in +2 degrees of caster on each side of car. Still not happy with his work. Currently I have the driver’s side steering knuckle removed from the car to modify it to receive the “large†upper all joint. While cleaning the casting of grease and road crud I made a discovery. The attachment bolt holes where lower ball joint attaches, as well as the ones to hold caliper, look to be drilled off register in a counter clock ways direction. By having holes drilled forward of spindle, to me, presets this assembly in an increased negative caster position. I measured the perceived off register difference in the casting, and it looks to be about .050â€. This would appear to be insignificant, except that 0.050†ark is scribed by about a 7 inch radius. When drawn out to full scale it looks to be 1 to 1.5* measured by protractor. Is this a plausible theory? [img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Brakes/100_1390.jpg[/img] |
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| Author: | Dart270 [ Sun Jan 23, 2011 5:00 pm ] |
| Post subject: | |
Sounds conceivable, although I've not heard of this before. The factory would have had jigs to drill these things, but I suppose a goof could have been made in mounting to the jig?? Take this opportunity to sell your KH brake stuff and switch to 73-76 spindles and stock 10.7" or bigger 11.75" brakes?? Just a thought... Lou |
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| Author: | wjajr [ Sun Jan 23, 2011 8:24 pm ] |
| Post subject: | |
[quote]Take this opportunity to sell your KH brake stuff and switch to 73-76 spindles and stock 10.7" or bigger 11.75" brakes??[/quote] Lou, This swap has crossed my mind. I’m guessing that these newer parts have the large bolt pattern, is this correct? Larger brakes would be nice, but at this time I don’t want to spring for larger tires, and rims, and plan on just getting the old KH stuff working correctly this year. FSM shows KH rotor as 11.04â€, and once working properly should stop the Dart fairly well. At some future date, if I decide to do a full restoration, I would most likely do a complete brake upgrade front & rear, and switch to large bolt pattern. Perhaps you could tell me, can an 8 ¾ axel be converted to large bolt pattern by redrilling and relocating studs, or are new axels required? The larger ball joint rubber dust cups cohabitate much better with tubular upper control arms than the small joint & bushing set up dose. Bill |
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| Author: | Dart270 [ Mon Jan 24, 2011 6:00 am ] |
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Bill, The KH brakes work very well, as long as they're not leaking (pistons). If working well, they are (still?) worth some $$ at this point in history, but may not be later? Yes, newer brakes are LBP and yes you can redrill 8.75" axles and drums for LBP (Moser or maybe local machine shop). Charlie Schmid and others on this site have done that. I think the only issue is making sure you locate the new studs correctly and don't get to close to any of the inspection/assembly holes on the axle flange. If you are at +1 caster with those KH spindles, then you are fine and I would not try redrilling all those holes on the spindle, if you were imagining doing that. Lou |
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| Author: | wjajr [ Mon Jan 24, 2011 8:16 am ] |
| Post subject: | |
[quote]If you are at +1 caster with those KH spindles, then you are fine and I would not try redrilling all those holes on the spindle, if you were imagining doing that.[/quote] No Lou, I don’t plan to re drill the knuckle castings. This caster imbalance has been a point of mystery for me. The line up guy also said that left front wheel is about a half inch closer to its rear’s mate than the other side. I don’t quite trust his ability, but it is hard to screw up reading a tape measure… These tubular upper control arms solved the caster problem nicely. If the front wheel is out of sync with the other side by a half inch, this may also be causing some of the weird unstable steering on long sweepers where the toe, or angle of “what’s yeah call it†feels like it changes mid turn causing the car to dart to the radius. Before I get too loco on this steering geometry stuff, I’ll replace the sloppy steering gear first, get a good alignment, and see how this car drives. Hopefully removing 5 inches of left to right steering wheel dead air will fix most of the steering deficiencies. I can report that when the power assist pump had its belt removed, the car handled much more predictably in long turns at all speeds. Bill |
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| Author: | Dart270 [ Mon Jan 24, 2011 12:51 pm ] |
| Post subject: | |
Sounds good! Steering slop is a terrible (and sometimes unpredictable) thing. Lou |
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