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Front lower control arm assembly and attachment 
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Joined: Wed Sep 24, 2008 10:05 am
Posts: 543
Location: 12,450 miles away from the Big Warehouse in Melbourne
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I want to make sure I am seeing this correctly and understand what I am looking at (and reading in the manual).

The front lower control arm, on the chassis end, is attached to the car by a long steel fulcrum shaft that has a stud on each end. The studs extend through the bushings.
The bushings are poured into stamped steel sleeves.
In order to disassemble this piece, the bushing has to be pushed out of one end, then the shaft slid out through the hole the bushing is mounted in, and then the other bushing pushed out the opposite end.
Reassembly involves pressing a new bushing into one end, then threading the long shaft through the opposite bushing mounting cylinder, and pressing the second bushing in and onto the shaft at the same time.
The diagram shows that there is a distance tube or spacer tool to support the two ends of the control arm while the second bushing is pressed into place. Is this for the spacing of the bushings in the arm or to prevent the collapse of the arm while pressing the bushing?

Last question:
Does anyone know the name of the guy who designed this some 50 years ago and why he made the conscious decision to so thoroughly screw me by designing this thing in such a way that it can not be altered or modified without replacing lots of expensive metal pieces?


Last edited by JT191 on Thu May 13, 2010 4:17 pm, edited 1 time in total.



Mon Apr 19, 2010 5:04 pm
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Joined: Tue Sep 16, 2008 11:54 am
Posts: 2542
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JT191 wrote:
I want to make sure I am seeing this correctly and understand what I am looking at (and reading in the manual).

The front lower control arm, on the chassis end, is attached to the car by a long steel fulcrum shaft that has a stud on each end. The studs extend through the bushings.
The bushings are poured into stamped steel sleeves.
In order to disassemble this piece, the bushing has to be pushed out of one end, then the shaft slid out through the hole the bushing is mounted in, and then the other bushing pushed out the opposite end.
Reassembly involves pressing a new bushing into one end, then threading the long shaft through the opposite bushing mounting cylinder, and pressing the second bushing in and onto the shaft at the same time.
The diagram shows that there is a distance tube or spacer tool to support the two ends of the control arm while the second bushing is pressed into place. Is this for the spacing of the bushings in the arm or to prevent the collapse of the arm while pressing the bushing?

simply, it's to support the arm to prevent it from collapsing when you press the new busshes in.
we use a specially fabricated support unit, made from heavy steel, to do the same job, as it's only needed when it's in the press.

JT191 wrote:
Last question:
Does anyone know the name of the guy who designed this some 50 years ago and why he made the conscious decision to so thoroughly screw me by designing this thing in such a way that it can not be altered or modified without replacing lots of expensive metal pieces?

i'd be guessing, but his surname would have been "mr. something japanese sounding - san"??
a question tho JT.... which area are u looking at modifing, and why? if it's for better camber/castor control, my race car is extremely modified in the front suspension, with some rear modifications as well, and while i have had this area apart to replace the bushes, i haven't needed to modify that area. the mods have been performed elsewhere (and some areas of a bellett suspension are in need of mods, no matter what!!), and it works very very well.
let me know if u need some pointers.
cheers.


Tue Apr 20, 2010 9:48 am
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Joined: Tue Mar 24, 2009 11:52 am
Posts: 843
Location: Sunshine Coast QLD
Car(s): PR95 PR20 WASP SWB NH Pajero Superchrged NT Pajero BF SR6 Falcon
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Can you tell me if these bushes available, if so where can I get them :?:


Tue Apr 20, 2010 11:24 am
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Joined: Wed Sep 24, 2008 10:05 am
Posts: 543
Location: 12,450 miles away from the Big Warehouse in Melbourne
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PR91 wrote:
i'd be guessing, but his surname would have been "mr. something japanese sounding - san"??
a question tho JT.... which area are u looking at modifing, and why?


I was a little frustrated and wanted to go into another chorus of expletives directed toward someone who had made my life more difficult even before I was born.

New (non OEM) bushings will not be cast in a steel sleeve and will be two piece with a shoulder. The halves will slide in from each side, then the center sleeve slides into the center hole of both halves.
If the long steel fulcrum shaft is used, it has to slide through the arm into position. Then there is no space to put the inner half of the opposing bushing in place. It will not press through the arm between the outer cylinder of the arm and the center stud of the fulcrum.
My best solution so far is to use a 2"x1" (25mm x 50mm) steel rectangular extrusion, about 8 1/2 inches long (216 mm). Drill the two rear mounting holes. Tap the front mounting holes and use studs instead of the U bolt. Tap the 14 mm holes to attach the arm in the ends of the bar and secure it with 14 mm bolts. Maybe turn down the center to make it look more like the original.
But the cost of the steel piece adds greatly to the cost of the set. And, because it's a reinforced redesign, it doesn't look original.

A bushing that will allow smooth movement of the arm, and support it with a shoulder on both sides to keep it centered and resist fore/aft movement, has to be put in from both sides, then bolted in from one side. Threading the center fulcrum through the center of the bushing, or pressing the bushing and it's inside shoulder through is not possible.
And the extra size of the new rectangular piece will be required because the threads of the end bolt holes will pass close to the mounting holes to attach the arm to the chassis.


Last edited by JT191 on Thu May 13, 2010 3:35 pm, edited 1 time in total.



Tue Apr 20, 2010 12:44 pm
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Joined: Wed Sep 24, 2008 10:05 am
Posts: 543
Location: 12,450 miles away from the Big Warehouse in Melbourne
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This project seems to have become an illustration of my motto: "If you are going to modify something, buy a spare one from the junk yard so you can screw it up and not have destroyed the one on the car, or switch back to the original if you find out the modified piece isn't working out."

The only problem being that the spare has to come from 8,000 miles away and costs 10-20 times more in shipping than the purchase price of the piece.

The rear arm bushings are rubber cast onto the center sleeve, and just take a little creative work with a bearing separator or puller to slide out. The finned outer surface of the bushing that rests against the arm allows some rust to grow. Possibly an issue for fitting a tighter tolerance bushing.

The front arms are where the fun comes in. They are modern style rubber cast between an inner and outer sleeve. There are two methods to removing these:
Get out the torch, burn the rubber, then run a hack saw blade inside the outer sleeve and try not to gouge the arm while cutting the outer sleeve.
Or,
Hand it to the machinist and let him use the press which won't require a lot of fill welding the gouges from the hack saw blade.

I opted for the second choice, and it seems the 40 year old bushings were pressed into the arms with some amazing force. Some of the welds on the arms were split while pressing the bushings out.
There is a little bit of a taper from the outside toward the middle, which is normal with the bushings cast into the metal sleeves, because they press into the arms and distort the metal on one end.
The lower arm structure wraps around to the inside edge of the cylindrical area the bushing installs into, and the weld will have to be ground down to allow the bushing shoulder to ride against the end of this cylinder.
The lower arm cylinders are symmetrical with a 45 degree chamfer on both ends.
The upper arm is asymmetrically a 45 degree chamfer only on the outer end of the cylinders.

I will start with redesigning the lower arm fulcrum so that the arms bolt in from the ends and find some appropriate shoulder bolts.

After that, I want to measure some things on the car to make sure my samples match and double check the thickness of the shoulder thickness of the bushings. It looks like 12 bushings, but it may take 8 different patterns to make them because the left and right halves are not the same due to taper and different shoulder thicknesses.


Mon May 10, 2010 4:50 pm
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