Cracked Lower Control Arm

truher · Post by **truher** » 07 Jul 2018, 16:06

Hi everybody,

Today I went to install some new bushings, Powerflex PFF88-601, link below [1], but in the last mm of insertion, the control arm shell broke with a thunk. See picture [2]. Is this something that just happens sometimes? Or am I doing it wrong? I used a lot of grease, and not too much pressure.

[1] https://powerflexusa.com/volvos60v70s80 ... 8-601.aspx

[2]

Georgeandkira · Post by **Georgeandkira** » 08 Jul 2018, 06:45

PM sent.

Post by **oragex** » 08 Jul 2018, 10:23

First time I see this. Yes a CA can crack or even break in two but it takes blunt and high force

The crack looks quite interesting, it even looks like there's two cracks starting each at different points on the outer edges. Feels like there was some hard impact on it. Was the old bushing hammered out? Was this a genuine arm?

One thing is, the surface should be clean and smooth. When it did the same, my surface looked mirror like, cleaned it, sanded a little, then brushed with a steel wire sponge. I has to be really mirror-smooth like, then some high pressure grease (CV joint type) helps. The bushing also goes into the freezer overnight and stays in a ziploc until right before inserting it. Inserting the bushing should not take heavy hammering at all, mine went very nice in with light tapping. Also good to rest it against a piece of wood instead of a hard surface.

Post by **SuperHerman** » 08 Jul 2018, 12:21

Not rare at all for Al arms. The trick the Jag people use is to freeze the bushing (shrink it) and stick the arm in boiling water (expand it). Then work quickly. Of course as oragex states make sure the surface is clean and some grease helps.

truher · Post by **truher** » 08 Jul 2018, 19:32

thanks guys. it was indeed the OE arm from 2001, and i pressed the old bushing out. it took quite a bit of force to do that, at least four tons, but the press was rigged clean and square, so i don't think the extraction hurt anything. next time i'll polish the shell -- i didn't think it was too rough, but i guess it was, and the little bit of corrosion on the old bushing probably galled it up a little more on the way out.

anyway, for now i'm just going with the stock parts to get the car rolling, i'll come back to the fancy bushings someday.

Post by **oragex** » 08 Jul 2018, 19:56

It is better and not that hard to rather cut the old ones out. Electric drill to make holes in the rubber all around, punch the center sleeve out, then pass a hand saw through the hole and cut two close grooves, then punch out the portion between the grooves. Pressing an old one out can put some stress on the alloy from much increasing friction due to corrosion (it is surprising how much this friction can increase the pressure needed to press out a bushing).