Front Axle Beam Replacement
There is nothing technically difficult about removing and replacing the beam on a breadloaf, the only problems are that it is *HEAVY* and that a number of things run *thru* the beam. The following is from experience replacing the beam on a '78, filled in with the memory of stripping a '79. Because I was doing a complete front end overhaul on the '78 at the time, I did some things that you may not want/have to do, but this it my story, and I'm sticking to it :-).
Before removing the old beam, you will need to clear the following from it:
the shift rod;
the booster and MC;
the parking brake cable;
the heater tube;
the brake calipers;
the drag link;
the speedo cable.
To remove the shift rod, remove first the shifter lever in the cab (2 13mm bolts at its base), under the bus remove the set screw at the junction of the front and rear rods. This is a square head screw about a foot back of the beam. Remove that screw, slide the front rod back 'til the front of it is off the pin, lower it and slide it forward 'til the rod is out.
The booster and MC... The front of the booster is a pin and clip at the bottom of the brake pedal, then there are 4 (?10mm?) nuts that hold the booster to the beam (get under there ***NOW*** and WD-40 them to death!!! and a couple more times before you try to loosen them). Now my mind gets foggy. I remember being forced to remove the MC with the booster, removing all the brake and fill lines from it. I tried to remove it from the booster, but I think it would not swing far enough out of the way to allow the booster to pass to the rear, as it must for removal of the booster. I forget, and will try removing the MC from the booster *again* this time, with the same bad luck, probably.
Parking brake cables were a doddle.... clamp a vise-grip to the square nuts and crank 'em off (liberal application of oil helps :)
Heater Tube... Hose clamp at each end. Basically simple, but be *very* gentle! That sucker is no longer available from VW and vital to the skimpy heat you do get!
Tie rods/Drag link... I was replacing these so I popped both ends of each, and tossed 'em. The drag link *must* come off, but if your new beam has good tie rods and ball joints, you need not remove them (I *think*)(but see below)
Brakes/steering knuckle...Since I was replacing the tie rods, drag link and ball joints at the same time as the beam, what I did was to loosen and pop the ball joints and tie rods from the steering knuckle and hung the knuckle/caliper/disk assembly from the frame. I also removed the trailing arms from the beam before I removed the beam. If you are installing a complete front beam assembly, you might just disconnect the hoses to the calipers, or remove and hang the calipers only, but you're on your own there..
However... I would advise removing the whole knuckle, as the beam is heavy enough by itself, w/o adding the 60+ pounds the knuckle assemblies add.
It's just the 4 bolts (?17?mm) on each end (famous last words :) I STRONGLY advise that this takes 3 people, two of whom should be fairly hefty people! Take 3 bolts out of each end (I left the rear upper bolt in, YMMV, I don't think it much matters) and put a jack under the beam, in contact with the lower torsion tube with a hair of tension on it. Release the last bolt on each side and reinsert it ~1 turn. Put one person on either end of the beam and a third controls the jack. The beam end folk each release their bolts, and the third lowers the jack *slowly*. As it lowers, the beam will want to tilt backward. The beam end folk should control this (yeah, right, just keep yer heads outta there!)
Once the beam is down, the beam end folk can lift it off the jack, rotate it and lay it down. Be careful, it weighs on the order of 100lbs, w/o the trailing arms or steering knuckles.
Is the classick "reverse of removal". Things to watch out for:
All beams are not created equal! You may find that your new beam is not the exact width of the frame (mine was, but I was warned about this, so I pass it on). If the beam is too narrow, you are SOL and walking til you find a wider beam. If it is too wide, then you *must* insert shims. I was very specifically warned not to crank the bolts to tighten it to the frame, or wedge it wider, as this will distort it, and cause a fatigue failure of the beam (I dunno, but it sounded bad to me!)
After you get the new beam up, and the bolts in loosely, while you are tightening them, have someone lay on their back with their feet against the lower torsion tube and press it back while you tighten. If not, the first time you brake the bus will take that rotational slack out suddenly. (Again, I was warned, did this, and have no idea how bad the consequences of not doing it are).
Further information available upon request, corrections/additions welcomed (it *was* 5 years ago, and I may have forgotten some widget), and I may update this in a week or two, when I do it again!
IMHO, you should allow a whole weekend to this. It is time consuming, and the piece is heavy and clumsy. I would not begrudge a pro the ~4-600 I have heard quoted for the job.
Lastly, I *believe* a '71-79 beam is OK, I don't know about the '68-70's tho, as they may not have the mount for the disk brake booster. There may also be some probelm w/early and late boosters. I sent one to David Schwarze off the '79 for his '73 and it was a different diameter and rubbed. The reason *may* be a change in beam mount points (I'm guessing here). Your best bet is a '76-79 beam, if possible, a '71-75 if available, or a '68-70 if you are willing to give up the brake booster.
Copyright H Steven Dolan 1997
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