Josh's FIAT 1500 Cabrio

6/14/2004: Assembling the Subframe

Since the last update, i’ve finished painting most of the suspension parts, including the subframe, control arms, and associated nuts and bolts.

Danny at Fun Imported up the street pressed in new control arm bushings, both upper and lower.

I test-assembled the upper control arms, and everything went together fine. I found all the bits and pieces and everything still fits. I couldn’t tighten down the end nuts very far since there’s paint in the threads. I’ll have to get a tap to take care of that- don’t have one large enough at the moment. There’s no rush- I won’t be tightening these nuts fully until the car’s weight is on the suspension, to avoid twisting the rubber in the bushings.

I attempted to test assemble the lower control arms, but found that the bolts would not fit through the bushings. It turns out that these things had a ridge that I had to sand out with a dremel before the pins would fit.

Much of the front suspension is assembled with one-time-use “nylock” nuts, so I ordered new ones from McMaster-Carr.

I also ordered some urethane front sway bar bushings from summit racing. Doug Hamilton mentioned these some time ago on the FiatCabrios mailing list. These are made by Energy Suspension (Part number 9.5156G) and should hopefully be a drop-in replacement for the stock rubber bushings. Unfortunately, I haven’t found any urethane substitutes for the sway bar end or control arm rubber bushings, so rubber will have to do there.

I had a nice set of sway bar end bushings, which had been installed on the “blue subframe”. Other than some blue overspray, they seemed to be in reasonable shape, so I just cleaned them off and will be using them.

While inspecting my spare set of front suspension pieces, I found that they had a little metal “nut retainer” behind the steering arm. It was bent over the nuts that hold it to the steering knuckle, to prevent them from ever backing out. These were missing from the “blue subframe”, so I stripped them off my spare set and cleaned them up.

These appear to have been originally left unpainted (just silver-cad plated), so i will add them to my batch of parts to be plated, rather than painting them black. I’m hoping to finally send out those parts this week- i’ve found two places that can do silver cadmium plating of car parts at reasonable prices. I’ll post here once I decide which one to go with and have some results to share.

Continuing with the reassembly, I found that the passengers’ side steering knuckle had some scoring on one of the trunnion shafts. I stripped down the spare one so I could compare. It has much larger shafts, and won’t fit the bushings in the (new) trunnions I want to use. The other knuckles must have been machined down and larger bushings fitted.

So i’ve got a bit of a dilemma. I think i’ll start by trying to smooth over some of the scoring on the blue one and see how it turns out. It may be “good enough”, since the scoring is way at one end. If it fits tightly and I don’t feel any significant play in the joint, I think i’ll go with it.

Note: In the process of reassembling the subframe, I used a number of diagrams and photographs for reference. I’ve put them into one page in the “Reference Information” section.

This is where things stand now:

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