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Uneven frame height

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Rob Glasgow

Rob Glasgow

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Before I began the restoration of my 1960 BT7, it sat unevenly in the rear. I measured the distance between the ground and the top of the rear wheel arches and the left side was 3/4" less than the right. When I removed the rear springs I found the left spring had about 1/2" less arch than the right. Thinking that was the problem, I had both springs re-arched at a local spring shop. I had them add 1 inch to the right spring and 1-1/2 to the left. After reinstalling them, the car still sits unevenly with the same 3/4" lower on the left side. Currently the engine is still out of the car and body panels and interior are not installed. The rear axel sits hard down on the rubbers mounted to the upper surface of the frame so the frame cannot sit any higher than it is now. In other words, putting more arch in the springs at this time will not allow the frame to sit any higher.

So what can I do to correct the issue? I'm hoping that when I reinstall the engine, body panels and interior, there will be enough weight on the rear to lift the axel off the frame and the frame will sit level. Any other ideas?
 
Still sounds like bad springs to me Rob.
 
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Hi Rob,
To me, what you are describing is not a frame measurement, but a body measurement. There is a certain amount of slop (I mean adjustment) with the fender mounting holes. I would check the distance from the frame to the ground where the spring shackles attach. That is the furthest outboard point of the frame and where a difference on each side will be easier to read.
 
Greg, Yes I did measure the distance from the bottom of the frame to the ground and it was also 3/4 lower on the left hand side.
 
Rob,
I do not think the axle should sit down hard on the frame, even with the engine out of the car. I'm not sure what would cause that, but I think you need to solve that problem first. Maybe some pictures would help?
Keith
 
Rob Glasgow said:
Greg, Yes I did measure the distance from the bottom of the frame to the ground and it was also 3/4 lower on the left hand side.
Click to expand...

Well, that is perplexing then. With the axle hard on the frame, the only thing I can think of at the moment is the tires or the frame buffers are somehow different.
 
Hi Rob,

I agree with Greg and think your issue is more with the mounting of the fenders and body panels. Since the axel is mounted above the frame and the springs deform upward, without sufficient counter weight in the car, the car would be too light to properly deform and position the springs. Add to the issue the fact that your springs are of the stiffer 7 leaf variety with little built in travel and, without engine, transmission, gas etc. pushing sown, I would expected that your rear axel would be resting on the top of the frame.

Over the years, I have noted that my BJ8P1 driver side was a little lower at the rear then the passenger side. I was told this was a common issue as most Healeys are driven without a passenger's presence and this difference in side weight will takes its toll over the years.

At first I accepted this explanation and both sides appeared to be much closer in height on the new springs. After a number of years, the rear height differences seemed to increase and this time I added one of the newer long leafs to the original set of 7 giving me a stiffer total of 8 per side. This change improved the ride and height but did not eliminate the difference in ground distance and a quick measurement of ground to frame showed both sides to be equal.

So why did my left side seem lower then the right? Panel Fitment. When the shroud was installed onto the inner fenders, my assumption was that positioning was as original as both inner fenders were cleaned and painted but original and never moved. However, not realizing, I did straighten some bends in the upper portion of the inner fender that I later learned was adjustments done at the factory to fit position the shroud. On later close inspection the corrections I had done changed the left side of the shroud to sit, at center, 3/8" lower then the right side. Not realizing at the time, a further deviation applied when installing the fender added further side height deviation to a point of becoming noticeable.

To address your issue, I would suggest you adjust your body panels (as they did at the factory) and adjust your inner fenders to allow your outer panels to sit evenly and consistently with each other and address any spring height differences only after weight is in the car and the car.

Hope this helps,
Ray (64BJ8P1)
 
Greg, I did check the tires and they are the same height. The rubber buffers are brand new and seem the same thickness. Since the axle is resting right on the top of the frame, I think the only solution may be to install bigger diameter tires on the left side.....not something I want to consider.

RAC, as I mentioned, at this time the car does not have any body panels installed. My measurements were taken between the bottom of the frame and the ground. I can only hope that after I install the engine and transmission there will enough weight to deform the springs and lower the frame away from the axle. I only wish I had taken more pictures of that area of the car before I tore it apart. How many times have I said that.....
I will post some photos when I get home.
 
This sounds odd. How can one side of the frame can sit lower to the ground than the other if the axle is tight to the buffers on the frame and the tires are the same size and inflated the same. Might your frame be thicker on one side of the car than on the other? Even with new springs, the axle on the 100-6 without the rest of the power train installed sits down tight to the frame;' so that part does not sound unusual.
 
Hi Rob, Before you go any further, you might want to consider doing the following, jack the car up to where the wheels are off the ground, put the first two stands where the rear outriggers meet the main chassis rail, and make sure they are at the same height. Then jack the car up at the front with the wheels off the ground and put the stands where the front cross member meets the main chassis rails. Make sure the stands are at the same height. By doing this you can establish whether this is a frame issue or a suspension issue.
Measure the distance from the bottom of the chassis to the floor. Both at the rear should measure the same and both at the front should measure the same. If they do, then it is probably a suspension issue if not it is a chassis issue.
I would not recommend using re-arched springs although they may appear to be the same the spring resistance may not be the same. If you have a weak front spring it will effect the ride height at the rear. If the left front spring is soft than the right rear of the car will sit higher than the left rear. This also applies to the other side.
All the springs in the suspension were under sprung to reduce torsional loading in the chassis. In other words the springs were not adequate to support the loads that are applied.Make sure the rear springs are matched sets. I have seen new springs when this is not the case and then there is tracking and handling issues. I would recommend using BJ8 front springs with the understanding it will increase the torsional deflection of the chassis. If you have any questions please don't hesitate to call me. 905-854-3555
You can check the body measurements while the car is still on stands. do not run different size tires on the car, it is not safe and can cause damage to rear axle,and handling issues.
Marty
 
Rob,

First, listen to Marty as he is the expert in this area. Second, what ever you decide, I strongly suggest you NOT put 2 different diameter tires on the rear of your Healey to compensate for any height differences. Third, engine, transmission, overdrive and fuel along with body panels, doors, and all else will definitely deflect your springs off the frame.

Keep in mind when reading my previous post that my comments were directed at addressing the fact the panels are what makes the car LOOK as though it is seated evenly and that perception is created by their placement... that is once any frame and undercarriage issues are addressed. You also mentioned measuring to the top of the wheel arch and not from the ground to the bottom of the frame. Since your frame is straight and not arched in the rear as a BJ8 Phase 2, are you referring to the inner fender sheet metal arch which is a less accurate point of measurement reference?

Again, I would strongly suggest calling Marty with any questions.

All the best,

Ray (64BJ8P1)
 
I had this same issue with my 60 MKI BN7. The left rear was lower than the right. I just chalked it up to driver only weight. Early this year 2 gentlemen sat in the car for a test drive. (car is for sale). Both guys appeared to be about the same weight. Any how when they returned from the test drive. The rear of the car was level. There was no left rear slant. The car has kept this level since then. The Healey has new springs, shocks, correct tires.
 
I know you said the frame is lower on one side, and that the driveshaft is sitting on the frame, but is the driveshaft tube also lower on one side?
 
Randy, No when I measure between the center of the bottom of the U bolt plate (directly under where the springs mount to the axle) and the floor, the left side is only 1/8" l lower than the right side. So I would assume the axle is almost parallel to the ground. It's only the frame that is 3/4" lower on the left side. I thinking the frame maybe twisted or bend a bit. I haven't had a chance to put it up on stands like Martin suggested, but that might help shed some light on what's happening.

Maybe all I have to do is convert it to a right hand drive and after sitting on the right side for 50 more years, the rear will be level......
 
Rob, as has been said here and I will confirm it, the axle housing does rest hard on the rubbers on the top of the frame rail when installed and the car is not loaded and the frame is resting on jackstands. I've attached the best pic I have from when I assembled my car. It is not the best pic for the subject but I think it does show the axle resting on the frame. I think your frame has a bit of a twist in the back. Dave.
 

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vette said:
Rob, as has been said here and I will confirm it, the axle housing does rest hard on the rubbers on the top of the frame rail when installed and the car is not loaded and the frame is resting on jackstands. I've attached the best pic I have from when I assembled my car. It is not the best pic for the subject but I think it does show the axle resting on the frame. I think your frame has a bit of a twist in the back. Dave.
Click to expand...

Yes, but is his car sitting on jack stands? I think it is sitting on the wheels, and the axle is still hard against the frame. That's not how my car is...
 
Rob Glasgow said:
Randy, No when I measure between the center of the bottom of the U bolt plate (directly under where the springs mount to the axle) and the floor, the left side is only 1/8" l lower than the right side. So I would assume the axle is almost parallel to the ground. It's only the frame that is 3/4" lower on the left side. I thinking the frame maybe twisted or bend a bit. I haven't had a chance to put it up on stands like Martin suggested, but that might help shed some light on what's happening.

Maybe all I have to do is convert it to a right hand drive and after sitting on the right side for 50 more years, the rear will be level......
Click to expand...

As I suggested above, did you measure the height of the frame rails - top to bottom - at that point on the car? These frames are constructed of relatively light material, and they can deform. Or someone may have beefed up one side of the frame and not the other.
 
Since your doing a full blown restoration just bring it to a shop that has a frame straightener and have him laser it to see if its straight
 
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