Front beam bolts don't fit well

[EVfun]

I'm having a little problem installing the front beam bolts. I chased the threads carefully with a tap and little open end wrench to get all the dirt out. The bolts will easily thread in by hand all the way without a beam. With my new Airkewld front beam I'm getting a lack of cooperation. I can get the left ones to start but it is clear they are dragging. With this kind of drag I can't properly torque the left side down, and the right side is farther off! On the right I guess I need to open the holes in the beam downward because when I do get them to start the beam is low on that side and the bolts quickly get tight as that side is coming up into the saddles on the pan head. Right now the right side is held to the frame with a large C-clamp and I cannot even start the bolts. The chassis is 56 years old but the frame head looks like its never been bashed. I'm guessing it is down to slight angular conflict, perhaps pervious over-tightening? They old beam came off freely, but the holes in a factory beam are just a little larger (13.5mm diameter instead of 12.7mm.) I know the right side is fighting a lot more than that.

I'm looking for pointers to look for frame damage, or old beam damage. I'm also looking for any similar experiences you have had and any solutions you have tried. Breaking out the Dremel and a small burr to open the holes in the beam clamps is the only thing that comes to my mind right now. Thanks!
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[clonebug]

I would drill the holes one size up until the bolts fit smoothly.
Just take them up a 1/16th at a time.

The pan head should center it well enough or else weld a little tab on the head and beam to make sure it gets put in the right spot.

As the guy said to me when he was replacing my framehead and I was worrying about a 1/32nd of and inch.
He said a 64 Galaxie had a 1/4 inch tolerance......side to side forward and back....alignment will take care of the rest.
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[slalombuggy]

The frame head would have to be seriously twisted to have the threaded inserts come out of alignment. They are in a tube that is welded in both the front and rear plates. You could not over torque the bolts and pull them out of alignment That is a very robust, layered part of the pan.

More like is that the holes are not drilled in the proper location in the new beam. Clamp the beam in the frame head and make sure the tubes are the correct distance apart and them open up the holes as needed to fit the bolts.

brad

[Q-Dog]

I would: Remove the beam. Install the 4 bolts. Measure their position. Measure the holes in the beam to see what is off. Send back the aftermarket parts if they aren't made correctly.
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Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[Busted Knuckle Garage]

I like Brian's idea. For what you paid for that beam it should bolt right in. Call Airkewld and make them aware of the problem,

Good luck
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Frank

[andk5591]

IF you are using caster shims, that could cause your problem...But yeah, I would measure everything - if the spacing is correct, then just open up the holes a little.
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D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
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There's more, but not keeping them...

[EVfun]

I can't blame the manufacturer without very carefully checking the car first. Most Buggies seem to be built on the frames of wrecked Bugs. I know from previous checking that the ends of my rear torsion housing and front beam (the old stock one) show the frame has about 4mm of twist, perhaps when it was shortened or perhaps something else. I know with the beam bolts 5 threads into the clean frame head that the left pair have their heads 0.5mm closer together that looks like it is a very slight difference in the angle they exit the pan head. So its not perfect, but I don't see any signs of frame head accident damage and original beam unbolted easily enough.

I am using caster shims. The fact they didn't want to rotate down enough to be even was one of my clues when I started the bolts. Leaving them out for a test fit didn't help the problem.

I figured out that a 5 inch long 3/8 bolt can be slipped into the frame head beam bolt holes from the back, and that will allow me to see how off the holes are. I can determine how much slotting will be required and should be able to determine where the error lies.

Thanks for the input. I will get some measuring done and report back. It might take a couple days since usually my wife helps me move the beam around so I can protect the nice finish.
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[Dale M.]

If old beams and shims fit good and new one doesn't suspect new one.... As a famous carpenter said, " measure twice, cut once"...

One thing I always do in frame heads us run tap complete through threaded, welded in inserts so bolts do not bottom out...Yes the threads do not always run all the way through...

Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[GS guy]

Make sure your bolts aren't just slightly bent EV. Roll them on a flat plate and see if any wobble shows up. Also try threading the bolts into the frame head (no beam) and check for parallelism and squareness/level with chassis. Does sound like the new beam might be a little undersized for bolt hole clearance, tolerance stack-up working against you.
Might also try some measurements with a piece of straight tubing "clamped" into the frame head and check squareness/level with chassis.
Jeff

Footnote - after re-reading your original post I'd start first with the new beam and some careful measurements. All hole locations square with the beam tubes, equal-distant to the tubes top and bottom, as well as matching general dimensions of your original beam. Aftermarked stuff I always suspect first for correct (or lack of) manufacture!
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[EVfun]

A couple of good points in the last 2 messages. My frame head threads do not go all the way through, but easily deep enough that the bolts will not bottom out. Then I checked the bolts for straightness, and they are not bent.

I hope to get the beam back off this evening, but I was able to get a good estimate on how far off the holes are. The right hand side needs to be slotted downward 5mm and the left side down 1mm. I got pretty good measurements with a 5 inch long 3/8 bolt. It is a reasonably close fit inside the 12mm threads and by pushing it up and measuring, then down and measuring, then averaging those out I could get a pretty good estimate of the center of the threads on the frame. Once I pull it off I will use a square behind the beam and under and them measure up from the bottom of the lower tube to the holes and compare them to my old stock beam.
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[Airkewld]

Beam holes are slotted left to right and are cut to 10.5mm. Please text me before you do anything to the beam. I have chassis's over here to try and create the same problem over here.
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[EVfun]

I won't do anything to the beam without consulting you first. I know some want to blame the manufacturer first, but so far I am not finding the problem by measuring. I'm at work and my notes are at home but what I remember from yesterday is that when I put a square on the back of the beam tubes, holding it so its on the back of both tubes and the bottom of the lower tube (establishing a reference is kinda a pain with round tubes ) I measured up from that square to the bottom of the bolt holes in the beam with a metric steel ruler. What I ended up with was it appears the new beam has the holes about 1mm higher. It's a 50.8mm tube compared to 52mm stock so that should reduce the measurement by 0.6mm. The hole bottom in the new beam is 12.7mm high (1/2 inch) instead of the 13.5mm round hold stock so that should increase the measurement by 0.4mm. As a result I should expect the measurement to be 0.2mm less with the new beam and I got 1mm more. That is not much and not like the problem I'm having.

The beam bolts 90mm long stock? If so I think I will order some longer bolts today at lunch, cut the heads off, and use them as studs to compare the fit of the stock and the new front end. I'm also going to be remeasuring, and trying to find more measurements to take later today.

A couple other observations. First, I have 21mm of thread depth in the pan head lugs (bolts screwed in by hand without the beam) and the lower beam bolts (with caster wedges) thread in 8mm. The steering box position is at a lower angle than stock so I will need to turn it slightly up. I cannot compare it to stock because my beam doesn't have the bumps for the steering box clamp used to select Bug or Ghia mounting angles. Instead it has 2, 10mm square and 2mm thick pieces of metal spot welded to the top of the beam on either side of the steering box (spot welds looks factory) that locate the box side to side. I could rotate the box to suit the buggy steering angle and it was low enough that I can see the long tie rod had touched the top of the frame tunnel a few times. What are the threads on the 2 little cap screws that locate the steering box clamp Pete? I'm going to need to put a couple set screws in there so I can rotate the the steering box and keep the grease inside.

Any ideas on what to measure next are more than welcome!
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[slalombuggy]

Put the stock bolts in. Take a straight edge that will reach across both horizontally and vertically. Run the straight edge across the sides of the bolts both ways so it scribes lines on the bolts. Measure from one line to the next. This should be very close to the centerline between the holes. But like I said, this is a VERY strong part of the car. The chances of bending the threaded inserts is close to zero. The bolts are fine thread so finding bolts off the shelf will be a bit of a challenge.

[EVfun]

Checking with a square does show the upper right bolt is just a tiny bit low and outward. The total error is about 1mm from a perfect rectangle with the other 3 at the point where the bolt heads would contact the beam clamps.

A detail I didn't realize before means my initial measurements are not good. The upper beam bolts will hit the bottom of the upper beam tube so you cannot wiggle a close fitting rod to find the center of the hole.

Right now I have 4 long bolts with the heads cut off in the pan head and the beam in place over them. To do that you must slip the beam on with only the uppers in place, and the steering damper has to be unbolted at the beam. Then the lowers can be started and the beam pushed back into place. Without caster wedges the bolts on the left can be easily turned by hand. The bolts on the right are riding against the bottom of the holes and pliers are needed to turn them. The upper ones are quite tight, however, on my test this afternoon the beam did push all the way into the pan head saddles. I expect the fit problem to worsen some when I put the caster wedges back in because that rotates the beam up around the top tube a little.

UPDATE: As expected, with the caster wedges in place there was no chance of seating the beam. If you think about this it makes sense. Adding caster wedges rotates the beam around the center of the upper tube. That rotates the beam holes upward. I cannot turn the bolts at all 4 bind against the bottom of the holes in the beam, and this pulls the upper tube down so I am no longer able to get the upper tube into the saddles on the pan head. Without caster wedges I would only need to slightly file downward the upper right bolt, the one that is just slightly off, to put all the bolts in with my fingers. With the caster wedges I would need a quite a bit more.
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[GS guy]

EV - time to become friends with a large rat-tail file! Maybe some slight clearance hole sizing (standard is 0.031" larger than the bolt diameter) on the upper holes? I don't recall having issues fitting caster shims on the last VW chassis I worked on, oh about 20 years ago...... except needing slightly longer bolts on the bottom. At the very least you could duplicate the bolt hole sizes from your old beam to the new one.
Jeff
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70's vintage Deserter GS buggy - undergoing transformation to Super GS!

[Airkewld]

Had a conversation on the phone yesterday. In my opinion, this is my theory. Pete had caster shims in his previous beam and when tightened down, the nutsert in the frame head moved ever so slightly to bring it out of line.

From our conversation, it was recommended to remove them for now until he deems it necessary to need more caster with his new set up. He can always install them, IMHO, he doesn't need them to start and should start with a clean slate of data.
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[Dale M.]

It's been my findings that almost every shortened VW chassis dune buggy benefits from caster shims... Many people have complained of erratic handling problem with shortened chassis and specially if running larger tires in rear... Almost all of the responses in the sambe is that caster shims have helped in handling issues... The real solution is to do a caster angle check (many documents on procedure on web) and find out exactly what the caster angle is... Industry standard seems to be about 7° degrees of positive caster, but a bit more seems to improve handling especially if steering is slow or sluggish in returning to center after a turn...

Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[EVfun]

I'm going to initially run without the wedges as it fits perfectly on the left and only the top right bolt hole needs work. Since the beam bolts only torque to 36 ft-lb I will clearance the beam just a little for the upper right bolt to zero out drag. The welded in lug doesn't want to move slightly up in the frame. I can pick up the front of the frame with the beam in place so cannot get much upward force on it without it threatening to hop off the jack stands.

I've never had a tight front end on the Buggy to know if I needed the shims. It has had some king pin play and vertical movement on the right one since I got it in the early '90's. In the last few years the lower right link pin ran out of adjustment range and was loose. NOTE, if a link pin starts needing more tightening that the rest it's a good sign the trailing arm bearing in the beam is loose and failing. Now I have a tight front end AND I have unusual wheels that should help stabilize the front too. My front offset is a lot more than stock, 14 inch Bus wheels with a +47ET. Stock is +33 and most aftermarket less. My more negative scrub radius should help with stability as road forces pulling back on one side encourage it to steer opposite that effect (instead of exaggerating it.)

I don't agree with Pete on why I have the fit issue. If using the caster wedges, with or without over tightening, moved the lugs in the frame that should mess with the fit without the wedges. It fits better without them. I recommend some minor updates In your beam going forward. My suggestion is to change the 1/2 inch high by 11/16 inch long holes with 4 round holes that are 9/16 inch diameter and move the center of the holes down 0.03 inch. Caster wedges will be needed on a number of modified VWs. If a Bug is slammed evenly the caster won't change from the stock 2 degrees (K&L Bugs.) Any rake on the frame will reduce caster, about 0.6 degrees per inch of rake for the stock 94.4 inch wheelbase, about 0.7 degrees per inch on a short wheelbase buggy. I expect I will only have 0.6 degrees of caster with my 2 inch rake (front wheels are 3.5 inches shorter than the rear and I am planning to lower the front just a little more than the rear.)
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[slalombuggy]

As I said in my first post. The tubes that the bolts go into are welded to the front plate where the beam sets AND to the rear of front section. You can not move those tubes by over torquing the bolts. The front beam and front bulkhead will be severely damaged before you move those threaded inserts out of alignment.

.6*s of caster is gonna suck for stability no matter what offset your wheels are. I ran .5* on my autocross buggy and it was not that great on the freeway.

brad

[Airkewld]