Front Suspension Mounts

I’ve finally finished the front suspension brackets and have started to set-up the A-Arm mounts.

I had one of those weekend ends where I ran out of everything. Sanding discs, sanding belts, grinding discs, band-saw blades, new lens for the welding hood, 13 amp fuses, etc. Every job I went to do the easy way, ended up taking hours. I hope I’m not alone in having these days! Be prepared; this blog is packed full of excuses.

The front end on this car is not standard – not even close.

The chassis is approximately 2″ wider than standard at the central drivers compartment, although standard width at the front. The chassis is about 2″ longer and the wheelbase has been stretched nearly 4″ to give the car a more aggressive look.

Coupled to that I’m using Audi RS4 19×9″ wheels all round. They are significantly taller than standard. If I were to mount these onto a standard Haynes Roadster, it would gain a jacked-up off-road style ground clearance. To counteract this, the suspension has been moved up-wards on the chassis, effectively lowering the body back down.

This car has got 25% anti-dive geometry (see anti dive blog here), so the mounts don’t even end up level to the base surface.

So that there is enough room for front 4×4 drive shafts, steering and suspension push-rods, the width of the A-Arms have also been increased, moving the chassis uprights backwards to match.

What I’m basically saying is, setting this up is going to a little tricky.

As you can see in the above shot, I’ve had a quick play. I made the mounts and brackets to a high tolerance in order to make this process as easy as possible, but even doing this, still means the process of getting everything right might take a few hours.

In the above shot, you can see a bar slid through the top suspension mounts (already slipped in picture). I’ll cut these bars down and turn them to a sharp point. Having a pointed tip on these temporary rods, will help me with accurate measurements. I have two digital spirit levels accurate to 0.1°, but even these don’t produce results as accurate as I thought they would. I found that you could move mount positions almost 0.5mm before they changed 0.1°. I’m a bit nerdie about getting suspension mounts 100% accurate, so I’ve devised a plan. Good old fashioned, bubble levels would normally give better results but unfortunately because of the anti-dive, things aren’t horizontal, so I’m stuck with digital.

The plan is to make special mounts for 2 laser spirit levels, so that they sit tightly and squarely onto 2 rods. These 12mm rods will be passed through the two suspension mount brackets on both sides of the car. The lasers both produce a large X-Y axis cross, which will be visible on the end wall of the garage. With the X-Y axis perfectly vertical / horizontal I’ll get 2 projected lines (Following me?) Hopefully these two lines will be parallel and the two points on the end wall at the same height.

I shone the lasers along the chassis table and marked a horizontal line on the end garage wall. A third laser is shining a line along the center line of the car. I’ll use this to double check any laser lines with CAD measurements. Any small error or movement in the height or width of suspension mounts will be amplified several times across the length of the garage and produce a large change in the height of the laser line at the garage wall. I can check all lines with predicted points and there distance from the projected center line.

Well it’s a good theory. I’m still to working on it and from just the brief try I had, clamping these bits in the right position was somewhat frustrating but promising. I also know, as soon as I move the MIG welder anywhere near, metal will distort and pull mounting points miles from where I want them.

There are fun and games ahead.

Haynes Roadster Front Suspension

Other articles of interest:

 

Is Round Tube stronger than Square?

Is round tube really that much stronger than square for use on a chassis? Or is it just clever marketing? A trip to the Stoneleigh Kit Car Show prompted me to do more research. I knew the answer was not going to be simple - I was right. As soon ...

Haynes Push Rod Suspension

The rear suspension features rising spring rate, pushrod suspension. It's all mocked up here with dummy push rods etc. Read more here. The idea being, the more the car rolls, the higher the spring rate seen by the wheel. It's what the formula 1 boys do. However, here are my problems: ...

MT75 4x4 Haynes Roadster

I've had a trial fitment of the MT75 Ford Cosworth 4x4 gearbox and it was a little tighter than I hoped. The gear selector mechanism; which will be removed and replaced; fouled the tunnel but this was a known issue. More importantly, the gearbox's transfer casing is a little close ...

Suspension Mounts

I've done the mounts for the front suspension A-arms and the Sierra Front 4x4 mounts. I'm not the first to mount a 4x4 front diff into a Haynes Roadster and at the speed I work at it's not surprised. It's not just a case of welding on some brackets there ...

Starting Again - Cutting It Up

It was decided that, although individual measurements often had small errors compared to the drawings, all these minor errors added up to huge errors. There were 27mm differences from one side of the chassis to the other and it had over 30mm of twist. Our goal was to have less ...

Plan of Attack

Having built and modified several cars in the past, with this build I knew it was vital that I laid out exactly what I wanted to do before I even picked up a saw or file. I’d had projects that started with live axles, swapped for IRS then ...

Chassis Type

Having quickly established that most pairs of measurements were different, the next task was to check all measurements against those published. In the process, establish exactly what type of chassis I´d purchased. The fact that measurements were different to those published would not be of major concern; as no ...

Chassis Collection

Having debated building a 'super seven' style car for decades, when a chassis came up on ebay with a reserve of only £0.99, temptation and curiosity took hold. The auction finished with only 3 bids at £56.55. Surely this was a bargain??!? A 550mile round trip would answer that. The unfortunate answer ...

Translate »

Web Design by Go Web Solutions