Checking A Rear Beam

[Anthony 1,000]

What's the easiest way of checking a rear beam to see if it's too far gone to be rebuilt?

 

As per my other post, I've found a couple of 309 GTi's in my local scrappy that I'm going to have the rear beams off. The beam's will be rebuilt as a matter of course, but I need to check that the beams aren't too far gone to be rebuilt.

 

I know the normal tale-tale sign is excessive camber on one or both rear wheels, meaning that the bearings have disintegrated. What else can I easily check without pulling the beam apart there and then?

 

Obviously if the rear trailing arm has any play in it then again I assume the bearings are shot, but then again a lack of play could indicate that the beam has siezed up which is argueably even worse.

 

If I try jacking the trailing arm up with a trolley jack, that'll show whether the beam is siezed won't it, as the trailing arm should be solid if that's the case?

 

Is there anything else I can check? Both cars have got about 115k on the clock and are 12 years old, so the rear beams will be at the age when they need rebuilding unless they've been done previously.

 

If it does turn out that the beams have had it, is it worth picking them up anyway for uprated torsion bars and/or rear ARB's (I assume these are stiffer on 309 GTi beams than 205 GTi ones?)

[jonah 1]

Difficult to tell the exact condition of the bearings without taking it apart, but any serious amount of play or a completely seized trailing arm should be easy enough to spot. Easier if you remove the shocks first as you can then move the trailing arms by hand and listen for any bearing noises.

 

Having said that I did all this when buying a beam from a scrappy and still found one of the bearings rusted when I took it apart. Could have been salvaged with a new bearing and arm shaft but I took it back instead and got another one with good bearings.

[Anthony 1,000]

Right, one of the beams had a siezed trailing arm and was showing excess camber, so I assume that beam is going to be effectively scrap.

 

The other beam seems to be OK - there's no excess camber, the trailing arms aren't siezed, and there's no play in the bearings. The condition will of course be confirmed when I take the beam apart to recondition it, but so far at least, it looks like a complete bargain for £25 including a decent pair of rear calipers.

 

Now all I've got to do is recondition it....

[pug_ham 240 3 Cars]

Only way to be sure is dismantling but at least you have got the better of the two to rebuild.

 

With the beam on the car you have hit all the checks you could do on the head, even if the car is no longer on the wheels then a pry bar between the radius arm & body should show signs of any movement or if the beam is seized up.

 

I know someone took a supposedly good rear beam from a 1.9 in to replace their knackered one to Shenpar & when it was fitted they went to lower it & the arm was seized solid & wouldn't even move up after being pryed down with the car on a ramp & lowering the radius arm onto a stand, the whole car lifted.

 

When I stripped my 309 rear beam which I knew to have camber on each side I assumed the drivers side would be the worst but the passenger side shaft was pitted beyond use & the drivers one still useable.

 

Graham.

[rotis23 0]

Right, one of the beams had a siezed trailing arm and was showing excess camber, so I assume that beam is going to be effectively scrap.

 

Why wouldn't a rebuild/bearing replacement sort this out?

[Anthony 1,000]

Why wouldn't a rebuild/bearing replacement sort this out?

Because the beam tube becomes scored from the shaft grinding away on it (since the bearing that sits between the two has almost certainly disintegrated)