Amazon: Brake System Upgrade

[940_Turbo]

Originally Posted by Derek UK

Excellent work as usual, on both of the parts. I suspect that finessing the last bracket to give a "gas tight joint" is overkill considering you're going to melt it with your Tig. Would you normally chamfer the edge anyway to help the weld to fill the junction?

Getting the joint nice and tight will make it significantly stronger. The idea is to fuse the two surfaces together. The weld shouldn't be bridging a gap effectively gluing the two together.

Nice work BTW.

[dheming]

Thanks guys. I will indeed be beveling the square tube, but only where the fishmouth is to aid penetration. The flat edge running horizontal is already going to 100% penetration due to how it's cut. As 940_Turbo said, good fit up is the key to strong, reliable joints.

Tonight I cut the tower to length and did some more smoothing. I'm going to pick up a large diameter sanding drum to chuck in my drill press to make this process easier. I marked the two rows of holes - the coilover bracket on the front and the lower control arm(5 possible positions) on the side:



I want to keep the coilover itself as vertical as possible so I think I'm going to offset the lower bracket to the inside of the car. This should give me more room to breathe up top when I design the upper mount. Also you can see the row of four holes in the tower for the bracket that has three holes. This allows for the one bracket to be used in four possible positions and still have three bolts securing it. Topmost position is stock ride height, then 1" drop, then 2" drop, and finally the 3" drop position as is shown in both these pics in this post:

[dheming]

Picked up a 2" drum sander today at OSH. Chucked it in my drill press and it worked great with a 60 grit roll. After cleaning up the fishmouth some more I drilled the middle hole on the lower control arm side of the tower. Pulled the rear axle out from under the wagon and I cut off half of the stock lower bracket and grinded the welds smooth. Then I tack welded the tower in its place:





Then I muscled the axle back under the wagon, hoisted it up with my floorjack, and reconnected everything. So far I'm pretty happy with how this Mk3 setup is coming together:

[john h]

Very nice work, as always. How much ground clearance will you have with the new mounts fitted?

John

[940_Turbo]

I like the workmanship but I don't like the coilover hanging that far down at all. Wouldn't it be better to cut through the floor and create a tower for it to sit in?

[Derek UK]

What is your rationale for moving the coilover to the front of the axle? Yes it can be physically shorter as it will move through a shorter stroke. Behind the axle it will need to move further for the same change of radius arm movement but, if the damper can accomodate it, will likely give more controlled damper and spring movement. The spring is on the rear on the original and the damper is much longer.
Can't fault the workmanship though!

[dheming]

Thanks for all the input guys. On the subject of ground clearance I have a few pics to show. Exhibit A - here is the rear of the Amazon with the tire mounted and a board to simulate the ground level, showing 5" of clearance:



Here is the front of the Amazon at 3" drop, showing 5.25" of clearance:



As you can see the crossmember will only have around 5" of ground clearance when fully lowered so I'm not too worried about the 5" height in the rear. Of course once the wagon is on the ground this height will be a bit less due to the tires compressing with all the weight. Exhibit B - my lowered Silverado has spring perches that hang super low in the front and I've been daily driving it since 2004 without a single problem concerning clearance:



Mounting the coilovers in front of the axle is more due to necessity. There is simply much more space to work with up top when they are mounted in front than behind the axle. Plus the frame rails themselves have reinforcing plates right where I want to drill holes for the upper coilover mount brackets, a definite advantage to front mounting.

[Derek UK]

OK, fair enough. As I said in an earlier post this is certainly an interesting technical exercise and your workmanship is excellent but to me it is a bit like reinventing the wheel. If it was combined with swapping in a 240 axle with discs and limited slip diff, combined with a front hub change to match later wheels, plus Wilwood front calipers and discs etc it would all be part of a grand scheme. Maybe that's for later? Currently I think that this set up would be out performed by fitting a set of suitably rated lowering springs and good, possibly adjustable, shocks to the standard suspension. Happy to be proved wrong and I am enjoying following the build process.

(another) Derek

[dheming]

This is indeed only the beginning of phase 1 modifications. I started with the rear since I thought it would be the most amount of fabrication work due to how much was being changed. Plus I'm less sure about how to approach the front setup. On this note it's been a while since I've collected my thoughts on all this so here are my goals for this phase:

Rear
Disc brake axle - I hate dealing with drums; allows use of later Volvo rims.
Posi unit - most likely a Detroit Locker.
Spherical links - superior articulation; more road feel.
Adjustable 4-link - ability to tune weight transfer characteristics.
Single-adjustable coilovers - easy tuning of suspension dynamics.
Some kind of scheme to allow for stock and lowered ride heights.

Front
Higher capacity brakes - larger OD, thicker and vented rotors; aluminum 4-pot calipers; bias bar setup; all new plumbing throughout.
Rack and pinion - worm and sector boxes give a vague and sloppy road feel not to mention have more moving parts to wear out.
Collapsible steering column - better crash safety.
Larger sway bar.
Revised geometry - the Amazon front suspension was designed for a high ride height and tall & skinny tires. I want to run it lowered with wide, 55 profile tires. After looking at mitch1871's project thread lately I've been considering doing a MX5 front end swap since that car has a trackwidth only 2" wider than the Amazon and has a much more modern setup. I would modify it's stock crossmember or fab an entirely new custom K-member to mount everything. I would modify the hubs to run the same PCD as the 1800 axle in back. Needless to say I have to do much more research, after I finish the rear.

[Derek UK]

There are many suppliers of custom Mustang II type front ends which can give you virtually any combination of track, brakes, springs and steering.
As you say, time is ticking with the Volvo steering box as there are no new internal parts and low mileage replacements are hard to find. Having said that, if they don't leak through the bottom seal (replace NOW if leaking) and they are correctly adjusted, they will last and last.
Thanks for the update of your future plans. Add an OD to the list if you're ever going to drive it outside of the city limits!