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Subframe problems I think

Discussion in 'The Hokey Ass Message Board' started by 63bigbird, Feb 25, 2010.

  1. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    I have a 40 chevy truck that was subframed by the previous owner. Its from a 78 nova. My problem is the camber, it has excessive negative camber. I checked the ball joints, a arm bushings, has new front springs, and there are no shims to remove to help improve it. I can jack front wheels off the ground, put it back down and it looks great. Drive it down the road (which is a darty ride) park it and wheels are negative cambered again. Am I overlooking something or am I screwed with this subframe. Also checked sub where it connects to original frame, no broken welds or flex that I can see. Any ideas.:confused:
     
  2. OldSub
    Joined: Aug 27, 2003
    Posts: 1,064

    OldSub
    Member Emeritus

    I agree on the pictures, but it sounds to me like something may be broken, or at least not well enough braced.
     
  3. rdemilt
    Joined: Jan 12, 2009
    Posts: 135

    rdemilt
    Member
    from so florida

    I had the same issue. I went to a local tire shop for a alignment with my ford that has a nova clip and they had no clue. I ended up at a real front end shop that does big trucks. They got it lined up within specs but suggested I invest in adjustable upper control arms sometime down the road which will allow me to gain additional positive camber. They showed me the catalog to purchase them from but I do not have it available right now, Sorry.
     
  4. MEDDLER1
    Joined: Jun 1, 2006
    Posts: 1,590

    MEDDLER1
    Member

    Did the guy who clipped it cut the upper control arm mounts and move them?I have heard of that being done to early chevys and having issues.Apparently there are people out there who think this is an easy way to lower them as well.I just picked up a truck that somebody butchered(its alittle newer) and thats what they did because some circle track guy told them it was the hot ticket im sure.(at least thats what I have been told was the hot ticket from a circle track guy)
     

  5. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    A arms are in stock location. The truck is not even lowered yet and I have this bad camber problem
     
  6. chaddilac
    Joined: Mar 21, 2006
    Posts: 14,021

    chaddilac
    Member

    I would think the springs are too short... maybe the wrong spring even though they are new?
     
  7. ecna
    Joined: Feb 16, 2010
    Posts: 128

    ecna
    Member

    Assuming something isn't actually moving and changing, Moog offers an offset upper control arm shaft and bushing kit that will give you additional camber adjustment. The part number is K6146.
     

    Attached Files:

  8. Dzus
    Joined: Apr 3, 2006
    Posts: 321

    Dzus
    Member

    If all the parts are right and nothing has been butchered, you could have a bent crossmember. We used to straighten those on the frame rack. You are basically moving the upper control arms back out.

    The aftermarket first came up with a set of offset control arm shafts to deal with this. Later the adjustable upper control arms came out.

    If it was mine I'd straighten it.
     
  9. badshifter
    Joined: Apr 28, 2006
    Posts: 3,534

    badshifter
    Member

    Has the clip been narrowed? Or the upper or lower arms narrowed? What angle do the upper arms sit at when at ride height? Pics, and more info will go a long way to help. I wouldn't drive it much with that problem hiding in there.
     
  10. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    The previous owner gave me some receipts. One was from an alignment shop where he had 500.00 worth of work. I do not know how good they are. the ticket listed moog coils #5006, moog rt upper control arm #6146. I am planning to take to local alignment shop that I know is good, see if they can help.
     
  11. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    Upper arms sit close to a 45 degree angle downward. Subframe has not been narrowed, A arms have not either. I am not sure if they are correct for year though. Not sure how to know. I will take some pics tomorrow during daylight and post them
     
  12. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    Would wrong spindles cause problem? No idea if they have ever been changed
     
  13. pic's will probably narrow down it down.
     
  14. badshifter
    Joined: Apr 28, 2006
    Posts: 3,534

    badshifter
    Member

    Upper arms sit close to a 45 degree angle downward.

    I think you're on track to finding your problem if they are actually 45 degrees like this 0\_/0 when viewed from the front?. I'll check back after pics.
     
  15. badshifter
    Joined: Apr 28, 2006
    Posts: 3,534

    badshifter
    Member

    Yes, in many ways from spindle angle to caster/camber to height, steering arm location etc etc.
     
  16. you really need to post some pictures
     
  17. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,822

    Mr48chev
    ALLIANCE MEMBER

    After going back and reading the first post again, the reason the wheels stand up rightafter you jack it up and let it down is that when the A frames dropped a bit with the weight off the tire went in towards the middle of the car a bit and the spot where it contacts the ground when you let it down is a bit more towards the middle of the car than before you raised it. When the tires roll a couple of feet or you bounce the suspension a few times the tires settle back to where they before. This is one reason you will always see a good front end man bounce the car a bit when he lets it back down on the front end rack if he has jacked the wheel off the rack.

    Are you positive that all four of the upper A arm bolts are tight? If there are no shims between the upper shafts and the frame and the bolts are tight (long wrench and reef on it tight) and the camber is still too negative there are two things that can be done.

    A. swap the shafts for offset shafts.

    B. have the subframe "rolled" This means that they chain the frame rails to the front end rack and use a bottle jack (usually 20 ton or more) to push the crossmember up rolling the rails out and in the process bringing back the positive camber.

    What happens with a lot of these frames is that over time and miles the weight of the car and engine causes the frame rails to turn in at the top reducing the camber.

    You do need to take it to someone who knows what he is doing and is setup to work on frames and subframes. Usually in any larger city or metroplex area there is a spring and frame shop that does truck, motorhomes and what not.
     
    Last edited: Feb 25, 2010
  18. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    Any way to measure or look to see if subframe is sagging and needs rolled.
    Trying to load pics having trouble, may need help from the wife Hope to have some pics Friday evening. Thanks guys for your input. I hope you can help me figure this out.
     
  19. metalman
    Joined: Dec 30, 2006
    Posts: 3,297

    metalman
    Member

    Instead of paying an alignment shop I'd concider having a frame shop spec it out. Usally not that bad price wise to get it on a frame rack and checked. 9 times out of 10 on a Nova subframe too much negative camber is a sagged crossmember. Very commen on those. Usally not too expensive to have it pulled either, especially if it's already set up on the rack. Years ago I use to do 3/4 Nova subframe clips a month, probably one out of 6 had a sagging crossmember. The frame guy at the bodyshop next door to me got real good at fixing those.
     
  20. snowtiger_40
    Joined: Jan 26, 2010
    Posts: 25

    snowtiger_40
    Member

    i was a front end guy for a long long time....first question I have for you....is it raked a lot? rear height will affect negative caster hugely....second, have you properly checked lower and upper ball joints....with the vehicle supported under the lower control arm.....thirdly, have you checked lower control arm bushings? sitting on the ground and flexing the lower control arm is the correct way to check this. Ive seen a million new alignment guys check front end parts with the front wheels hanging and lifted on the frame. sometimes its nessesary to sacrifice a little caster to get the camber you need, just remember you need some caster for driveability. My guess is lower ball joints may be worn.
     
    Last edited: Feb 25, 2010
  21. 63bigbird
    Joined: Dec 27, 2009
    Posts: 131

    63bigbird
    Member

    I can't get pics to load as an attachment. I have an appointment at shop in the morning. Will see what they say.
     
  22. lwin 517
    Joined: Mar 6, 2010
    Posts: 1

    lwin 517
    Member
    from Ohio

    New to the board and found this thread, on a related problem, My 56 Chevy 1/2 ton has a 75 Chevy Camaro subframe installed by PO. It was a bit too low so I installed bigblock station wagon springs. Needless to say it rides WAY to hard, almost no give. I know the Camaro was about 3700 lbs anyone know what the 56 pickup weighs? I am going to have to go back to a lighter spring and need to find one that will be more compatable. Any help / ideas would be much appreciated.
     
  23. Doraville
    Joined: Apr 22, 2008
    Posts: 50

    Doraville
    Member
    from Georgia

    I have a 1952 Ford F1 pick-up, and the previous owner had installed the front clip from a '79 Monte Carlo to get power steering and disc brakes. I have similar issues to both of you. In addition to the good suggestions offered on this thread, you might also check a thread that I started over at the FTE forum.There are several good suggestions there, including a couple of suspension shops that may be able to help. I've contacted Eaton and am waiting to hear back from them.

    I'll stay subscribed to this thread and will post what I do next after I decide what to do.

    Peace,
    -DV
     
  24. rpol7966
    Joined: Sep 13, 2006
    Posts: 226

    rpol7966
    Member

    GM cars from the '60s and early '70s are all known for sagging crossmembers. As earlier stated, the weight of the engine and the constant pounding of the suspension from normal driving cause the suspension crossmember to "roll in". This makes it impossible to make proper camber adjustments.
    This can be corrected by pulling the structure back on a frame machine or offset upper cross shafts in the upper control arms.
    I have a '67 Chevelle wagon that has this problem. Had the front end aligned and could not get the camber set correctly. Went to a local yard that has many old '60s A bodies. I measured the distance between the mounting surfaces for the upper control arm cross shafts. This distance varied as much as 5/8"!
    Any time that these GM front suspensions are used, they need to be checked and possibly jacked apart a little beyond what is factory specifications. They will sag again unless reinforced!
     
  25. ironeye
    Joined: Feb 9, 2010
    Posts: 11

    ironeye
    Member

    Same situation here. 1963 F100 unibody longbed with a 1979-81 Camaro subframe. Over the winter we replaced every front suspension part.

    When getting it aligned, we found the center link was askew, so I sourced a used Camaro pitman arm to replace the Ford part and also put in a Camaro reman steering gear. Had much fun doing Chevy box to Ford power steering hose.

    Long story short... I still have negative camber. Not to mention, it sat lower on the right side by about an inch. The new springs helped a lot but it's still not quite level. This truck was thrown together with unrestored junkyard parts and the "paint over mud" mindset.

    Reading this forum seems to make me think the only solution is the Offset Upper Control Arm shaft and bushing, or the frame shop to bend back the frame.

    Really not sure which is the better way to go. Which is cheaper; which is more reliable? Where do you reinforce the frame after pulling it back to spec? How long will my brand new tires last if I do nothing? Send comments, please.

    How's that for my first post.
    Phil
     
  26. Doraville
    Joined: Apr 22, 2008
    Posts: 50

    Doraville
    Member
    from Georgia

    Just an update on my situation. I was able to get my camber within spec by installing the MOOG offset upper control arm pins. However, I still have a problem with the truck "wandering". I went back to my alignment guy and had him drive the truck. He put it back on the rack and discovered that I also have too much negative caster. He adjusted it as much as he could (I'm now at -3 deg, spec is +2 deg), and it drives much better now. I'd like to find a way of getting more positive caster without cutting the subframe loose and re-attaching it. Maybe offset ball joints or "problem-solver" control arms? Any suggestions would be appreciated.

    Iwin517, I also went through the whole coil spring sizing process recently. I'm going to write-up a procedure on how to do it using a standard MOOG spring spec chart and post it.

    Peace,
    -DV
     
  27. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    We always ordered these when they needed replacement. The factory didn't provide enough adjustment when they were new. Moog would not have made them if it wasn't a common problem. These were made for the daily drivers back in the day and not a street rod part.
     
  28. Doraville
    Joined: Apr 22, 2008
    Posts: 50

    Doraville
    Member
    from Georgia

    I had almost the same situation with my '52 Ford F1 with a Monte Carlo clip. I decided that I needed to buckle down and learn how to go about selecting coil springs. The break-though came when I found a complete Moog spring spec chart. (By the way, if you're reading this way in the future and the link no longer works, PM me and I'll send it to you in a spreadsheet).

    The first thing that I needed to do was figure out what springs were on the Monte Carlo clip from the factory. I went to Rock Auto and found that it most likely had Moog #5602 springs on it. Looking at the spec chart, those springs have a spring rate of 347 lbs per inch, and are 15.88 in. uncompressed.

    The next thing that I needed to know was the weight of my truck. I took it to the local scrap yard and had them weigh it. It tipped the scales at 1940 lbs at the front wheels. With this weight on the stock Monte Carlo springs, the compressed length should be [15.88 - (1940 lbs/347 lbs per inch)] = about 10.3 inches. I also knew from sight that this height was about an inch lower than I wanted to be.

    Now all I had to do was find a set of springs that would give me a comparable spring rate and a compressed height of around 11.3-11.5 inches. There were a number of choices that would have probably worked but I went with the Moog #5006 springs which have a spring rate of 355 lbs/in, and an uncompressed height if 16.88 inches. With the weight of my truck on them the compressed height should be 11.42 inches, a little over an inch taller than where I started.

    Anyway, I ordered the Moog #5006 springs from Rock Auto for $83 and installed them. I don't know why, but I was very pleasantly surprised that it all worked exactly as the calculations predicted. I love it when this happens.

    Hope this helps...
    -DV
     
    Last edited: May 1, 2010
  29. Doraville
    Joined: Apr 22, 2008
    Posts: 50

    Doraville
    Member
    from Georgia

    I have read and re-read this thread at least 8 times. The more I think about it, the more I'm concluding that this is the best advice.

    -DV
     
  30. Doraville
    Joined: Apr 22, 2008
    Posts: 50

    Doraville
    Member
    from Georgia

    Just a quick update on my issue on my '52 Ford F1 with a Monte Carlo subframe. My "wandering steering" was due to lack of caster. This could have been due to a sagging cross-member, or because the people who did the frame splice didn't pay enough attention to caster when installing it. As a side-note, I have discovered that a lot of front-end alignment guys tend to ignore caster (maybe because normally it doesn't change?).

    Because the upper A arms on the Monte Carlo's attach on the inside of the frame, adding shims to get more caster will subtract camber, and I didn't have any camber to spare. After some debate and much deliberation, I decided to take the advice of several people here and take it to a frame shop and have them spread the cross-member to give me enough camber so that shims could be added to get the caster that I needed.

    Good frame guys are a dying breed, but after a lot of asking-around I found a guy that understood what I needed and was able to do it. He spread the cross-member about an inch, which gave the alignment guy the camber that he needed to adjust the caster. The truck now drives as it should.

    Peace,
    -DV
     

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