First time FCAB replacement - harder than I thought

[vachss]

I've been reading for years, here and elsewhere, about how replacing the front control arm bushings was a quick, easy and worthwhile job. I'd delayed way longer than I should, but finally decided to do the job over the holidays with 118K on my Z4 coupe. Picked up a set of Meyle bushings with the heavy duty rubber and was ready to go.

Getting to the control arms was straightforward and much like the other DIYs out there:

Get the car up on jackstands on the front two lift points.
Take off the front wheels
Drop the engine brace (or whatever you call the hunk of metal held in by 8 bolts) and the FCABs are right there ready to be unbolted.

So far so good, then it got more complicated.

Using 2 jaw puller to yank the FCAB off the frame I found that "lollipop" housing was coming off but leaving the rubber behind. So I had to stop and build an FCAB removal tool as shown:



Unfortunately I wasn't snapping pictures while under the car so these are all from afterwards. Imagine the control arm coming in from the left hand side of the picture through the bushing shown. The C-shaped plate I made slides over the control arm and sits against the bushing. It's just a 1/4 inch thick 3" diameter Aluminum round I had lying around in which I cut a 0.9" slot that matches the width of the control arm near the bushing. The arms of the puller pull on this C-shaped plate rather than the bushing itself and allow the whole FCAB, rubber and all, to be pulled free.

The next part, again, started like the usual DIY instructions then diverged:
Squirted a bit of silicone lube on the bare control arm and inside the new bushing and pressed it on partway by hand. I then tried using various mallets and hammers to get it on the rest of the way and got nowhere. Time to fabricate tool #2:



This tool consists of a steel rod with two holes tapped for 1/4-20 separated by 5 inches. I then drilled a mating plate with 1/4 inch clearance holes also separated by 5" and connected the two with a pair of 1 foot length 1/4-20 threaded rods. To insert the FCAB the steel rod goes through the hole in the control arm, the threaded rods go above and below the bushing and the flat plate sits against the outside of the bushing. Sequentially tightening a pair of 1/4 bolts pulls the plate against the bushing and draws it onto the control arm.

Both these tools are quicky garage shop versions of tools sold by BavAuto (whose DIY video I studied before starting). I'm lucky enough to have a machine shop sharing space with the Z4...

so fabbing these tools only added maybe an hour overall to the job, but without them or some equivalent I would have had a much harder time.

Even with them I still found that one of the FCABs, once mounted on the control arm, absolutely refused to mate up with its mounting holes. I ended up having to loosen up the other mounting points on the control arm before I could force it on and then tighten everything back up.

In short, replacing the FCABs ended up taking me a whole afternoon and evening (rather than the 45 minutes some DIYs advertise). Some of this is due to fabrication time and head-scratching time, and some is no doubt due to my own inexperience/incompetence. But I've done a fair bit of DIY jobs over the years and this did not feel like a 1 hour job. Maybe with air tools, a lift, all special tools available (and fitment that didn't fight me), but crawling under the car with hand tools I would budget a good 2-3 hours if doing it again.

[StickMon]

Aren't those supposed to be offset?
Doesn't look like it in the pic.

Thanks for the tips. I still have stock replacements sitting in a drawer.
When I get around to it I'll expect it to be not as easy as it looks.

[vachss]

Originally Posted by StickMon

Aren't those supposed to be offset?
Doesn't look like it in the pic.

Offset FCABs are for the Z4M (and E46 M3). Centered units like the ones shown are for non-M E46s and Z4s (like my non-M Z4 coupe).

[Shipkiller]

vachss is correct.

[Incompatible]

Good info, thanks for posting. Like your garage/shop.

[The HACK]

Originally Posted by vachss

Even with them I still found that one of the FCABs, once mounted on the control arm, absolutely refused to mate up with its mounting holes. I ended up having to loosen up the other mounting points on the control arm before I could force it on and then tighten everything back up.

Two things.

1) Prior to removing the FCAB, use a permanent marker and mark on the control arm the exact position of the stock bushing on the arm. If you're off by a millimeter it increases the degree of difficulty by several magnitude.

2) Lift the suspension kingpin slightly to alleviate the downwards pressure exerted by gravity. It will make aligning the two extruding holes to the FCAB lollipop easier.