i bought some Lakewood traction bars.. they sit pointing down in the front.... they should sit straight.. it seems like that's because the u bolt brackets on the rear axles are not straight up and down... the U bolts actually face slightly towards the rear.. anyone running aftermarket traction bars and did you run into this problem???
Yup 2 options They're are wedges that range from 2 degrees to 6 degrees that you can install between the leaf springs and traction bars. Or you can cut and weld the traction bar to raise up toward the spring. Just leave them bolted on the car and use a Sawzall and cut up wards on the rectangle tube, don't completely cut off. Leave the top side intact. Bend upwards as far as needed and weld in the area you cut.
I seen the wedges on their site.. out of stock. for now... that's the first route ill try though... theres a rubber pad between the spring and plate.. directions say leave that in there.. so wedge between the plate and the pad or between the pad and spring?? and I removed the factory traction bar on the passenger side... should I have left that in there?
1968 400 Coupe, verdoro green, black vinyl top 1968 400 Convertible, verdoro green, black top 1971 Trans Am, cameo white, auto 1970 Buick Skylark Custom Convertible 350-4(driver)
I'm really wishing at this point I would have left this one alone... lol..... I was under the impression there was a hole in the axle to line up the leaf sprig to the axle... that is not the case.. theres a pin on the leaf spring.. but no hole in the axle... thoughts???
Yup The top insulator has a hump on the top and should have the hole where it sits on the spring and the bottom plate has a hole to line up with the pin on the leaf spring.
Yup The top insulator has a hump on the top and should have the hole where it sits on the spring and the bottom plate has a hole to line up with the pin on the leaf spring.
that's what I have.. but what keeps the axle lined up side to side on the springs?
right now the u bolts holding the axle in place slant backwards...should they face straight down?.. I cant really find a good picture of it..... I thought there was a pin coming out of the axle that lined this stuff up.. but that's not the case at all.. the rubber boot has the hole and it sits over the pin in the leaf spring... without an alignment pin of some sort how do you straighten the axle to the car???
The pin is on the bottom of the leaf spring and fits into a hole thru the insulator and into the hole in the bottom plate the saddle and the leaf spring set the angle of the axle, can you take some pictures I might be missing at what you are trying say
Do you have multi leaf springs or single leaf springs? I was under the impression single leaf spring perches did not have a center hole. Multi leaf spring perches have a hole in them, the head of the spring center bolt goes in this hole, that lines the springs/axles up side to side.
Are the rubber bumpers on the front of the bars touching the bottom of the springs thus forcing the front of the bar down? If so they can be cut using a hacksaw. The spring perches welded to the axle housing tubes are not necessarily horizontal after attached to the springs. If they are angled down use the wedges as mentioned above.
I'll attach a photo of a single leaf perch, a multi leaf perch and photo of a multi leaf with a spring in the perch. Obviously the spring in the multi leaf perch will have to have spacers installed so the spring will be clamped correctly but it gives you the idea. The head of the center bolt on the bottom of the spring fits in the hole in the perch. If you have a perch without a hole and do have a protruding center bolt head you could drill a hole in the perches to accept the bolt heads. The rear axle assy on my 68 is [sadly] from a 69 Camaro, the spring perches did not have holes in them but small indents that the low profile bolt head could sit in.
A photo of mine as it was when I bought it, Notice the single leaf perch with multi leaf spring. The bottom leaf is only half length, front half of spring has four leaves the back has three. These were attached with four 5/16" T bolts and not U bolts, someone put one ubolt on this. I would suggest onyone with the T bolt set up take out the T bolts and replace with U bolts. If your running any kind of power I suggest replace with 1/2" U bolts. As the spring is way too big for the perch the shock bracket is warped from tightening the nuts down on the bolts. There is also not room in the perches for the rubber pads, the pads are too wide for the perches. I have since modified this and installed Compitition Engineering traction bars
Jman, Can't be sure from that photo but it looks like you have a 67 housing and by the look of your spring perches the car originally had mono leaf springs. The mono leafs had a pin that protruded from the bottom and fit into a hole in the shock plate. That's how it looks in that pic anyway, maybe a couple more pics of the springs sitting in the perches? It looks like multi leaf springs in mono leaf perches, If that is the case you may have to remove the perches and weld on some deeper ones, or modify yours so they are higher and somehow put a hole in the center for the spring center bolt to sit in. I think some of the mono leaf perches sat right against the axle tube, if that is the case and you drill a hole through the center of the perch you would start drilling into the tube. Is the spring center bolt hitting the spring perch? Seems to me the multi leaf perches sit higher off the axle tube to allow room for the center bolt to protrude through.
Maybe if you had a 6 degree wedge, with a hole in it for the spring center bolt, welded to the bottom of the perch? You would also have to check if that would adversely affect your pinion angle.
It also seems to me the multi leaf and mono leaf shock plates have the shock mounting holes at different heights to compensate for the difference in thickness of springs and perches.
I'm just throwing out thoughts i'm definitely not a suspension expert.
it is mono leaf perches with muli leaf springs... the pin does not hit the axle.. and the bottom perch is to be removed and replaced with the new traction bar.. when I'm done cleaning under there and all painted I'm going to try the 6 degree wedge and see how it looks... I'm not much for welding new perches... maybe its time to think posi rear end with muli leaf perches!
Agree with blue bird. If the multi leafs snug up tight and flat into the perches the bolt protruding through the hole in the bottom shock plate will suffice to keep everything in position once it's all bolted up. Sure the spring perches for the mono leafs aren't as deep but.they will stil hold the spring from moving out of place. Best not to use the isolators between the spring and perches because it will move the spring that much more out of the pocket. I agree you should go to some U-bolts to hold everything together. The original traction bars are probably what set your pinion angle. Not sure what type of traction bars you plan on installing but they may take care of that issue after bolted on as well. You want around 2degrees looking down on your pinion angle. Never want it straight with the driveshaft.
they do bolt up ok.. just the perch seems to angle backwards quite a bit.. you car see it in the pic.. the traction bar has the bottom perch attached.. just seemed so odd that id have to use a 6 degree shim to straighten the traction bar out...
Just so we get straight what you're telling us, does the perch [the part that is welded to the axle tube that the spring fits in] have a hole in the center? If not where is the bolt that goes through the center of the spring positioned? The lower plate that is bolted to the bottom of the springs is the shock bracket, it clamps the spring in the perch and has a place to mount the shock. The lower plate/shock bracket has a hole in it, that the center pin of the spring fits into, after the whole shebang is bolted together the lower plate holds the spring in position. When one installs traction bars the lower plate is usually removed and replaced by the traction bar. As for the angle, mine are 1-1/2" lower [closer to the floor] at the front of the bar than they are just ahead of the spring perches. The front of the bar is 2" below the bottom of the spring, which is good as the rubber bumper at the front of the bar is just about 2" high.
Do you have new springs? Have you had the springs re-arched? Are they old springs that are somewhat clapped out, not unlike mine? I'm sure if you optained five sets of Firebird springs of various spring and load rates and tried them on your car, one set at a time, the angle of the perches would be different in between all five. I'm also quite sure the angle of the perches, in relation to horizontal, will not be the same after 40 years of thrashing than they were when first installed.
you almost answered my question with that picture.. that's exactly what my traction bars look like installed.. I thought they were supposed to be level and not pointed down at all...I also bought a kit that has spacers to convert the mono to multi leaf perch..... if its not a huge issue to have them point down slightly that takes up one issue...the main issue I have now is the alignment of the axle to the spring.... there is no hole in the welded perch on the axle... the pin in the spring does poke up about 1/4 inch out of the top of the spring but there is an insulator with a hole in it covering it...so it sits flush in the perch... what I don't understand, and maybe I'm just over thinking it... but, with the axle loose from the springs, I can roll the axle forward or backwards.. the axle is not attached to the car at all... what lines it back up exactly where its supposed to be.... is this a measurement from a certain point? centered in the wheel well?? it just seems odd there isn't a set position to put it in... it seems like it could bolt to the spring anywhere.... in other words... if I was installing a whole new rear axle.. how would I make sure its lined up correctly..
I was looking at those perch pics a little closer.. it does look like the multi leaf perch HAS a hole in it...but the mono doesn't....and In the pic of the 3 leaf there is no rubber insulator in there on top.... that hole in the multi leaf perch would certainly solve the alignment issue...
OK so, you have mono leaf perches with no hole in the center, you have multi leaf springs but the center bolt has been ground down to only 1/4" in height, You have an insulator in the perch on top of the spring with a hole for the center bolt, Once you loosely assemble the springs, axle and shock mounts/lower plate, you will position the axle so the pin is through the hole in the plate. Once you tighten it up that is how the axles are aligned. That is how the stock mono leaf springs are assembled. The multi leaf spring is a better idea with the hole in the perch. IF, only if, you can put a hole in your mono spring perch without drilling into the axle tube, that would position the axle correctly onto the springs. I think it is a good idea to get rid of the upper isolator in the perch and have the spring riding right against the metal of the perch. The rubber isolators are there to help the rubber bushings in the spring eyes and shakles reduce vibration and harshness from the road. The rubber isolators can also allow movement of the springs in the perch which can be a cause of a broken center bolt. The rubber isolators can also compress enough to alow the center bolt to make contact with the perch if there is no hole.
So my suggestions to properly align your springs and axles are: Drill a hole into the center of the perch, if possible, to align the axle to the perch. You may be able to drill in deep enough with a 1/4" drill or 5/16" drill then finish with a proper size drill that has had the point flattened out if neccassary. Then install without the rubber isolator; If drilling a hole in the perch is not an option, make two isolators out of steel the same legnth as the perches and slightly thicker than the height of the center bolt. Place the steel isolators over the center bolt and align the isolators in the perches as you assemble the axles and springs. That will position the axles in the correct position on the springs; Retorque the ubolts after the first outing then after 50 miles then after 500 miles. Just torque to spec, don't over torque. Loose ubolts may cause leaf or center bolt breakage.
Can you post a photo of the kit you have to convert the perches to multi leaf?
Agree. One extra little thing...if it was me I would try and fix a way to keep that upper spacer plate in the proper place by welding it to the perch so you don't get too much movement of the spring. Just a tack bead on either end would do it.
thanks for all the help guys...... that kit is just a WAY over priced couple of spacers from Detroit speed... they go thru the u bolts.. i'll post a pic when I get it all back together..
I found the kit you mentioned. I agree a bit expensive. I think Robert has a good idea tacking the plates in the perches. If you can't do that position the plates in the perch and mark the perches and plates so you know they are centered after you assemble everything together. Once it's clamped it should stay in place, welding the plates would just be a bit of insurance.
This is my set up on my 68 I have monoleaf with 200lbs rate. The car was sitting to high so I cut and modified the spring perches to lower the back of the car about 2 inches. I have a 4 degree wedge in between the slapper bars and the springs but I also cut and welded the bars to bring up closer to the spring eye.
That would put a bit of twist into the system, those slicks would most likely put my diff on the pavement. That's the weakest link in mine. Looks like you've added about two inches to the depth of the perches, that would add about 76.5 pounds of torque to the perches with my build. My 255/60 R15 BFGs are the safety valve, they spin, slicks grab.
I have an 8.2, unfortunately it's a c-clip off a 69 Camaro. I didn't realize it wasn't a BOP until I discovered the rear track was one inch narrow. I put one of those girdle rear covers on, don't know if they help but I thought it can't hurt.
I'm thinking this project turned in to a lot more than I was expecting.... this is how it ended up... I couldn't use the spacers from Detroit speed because of the wedges... its still not sitting flat.. it just doesn't seem right.. I'm thinking the only way to use these bars is to cut and weld them like big chief said... I love the look.. maybe just need different traction bars..
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