Rear control arms
Q I may need to replace the rear suspension control arms on my 2004 Mk1 Focus. Last year I tried to change a coil spring and remove the connecting bolts; eventually I removed the nut of the inner bolt. I could not then move the inner bolt or turn the outer bolt as I believe they are seized to the inner surface of the bush metal tubes.
I was advised that to remove the bolts, I should cut through with a thin blade. Is this the best way to remove and have you carried out this job?
If so what type and size of blades should be used and is there access for the normal 4.5in angle cutter? Have you any alternative methods?
The coil spring was changed by a local garage who had a spring compressor that had two arms that accessed horizontally from the side and compressed the spring vertically. I would like to have seen it in action.
Barry Ross A I can understand the worries you have regarding the removal of the rear suspension control arms, and I do know that these can be extremely difficult to remove after the bolts have been in place for several years. This is something I have had to carry out a number of times.
The first step is to ensure that the bolts and fixings have been coated in a penetrating oil which has been allowed to soak in. The first attempt should always be to undo the bolts as intended rather than to cut through the shank of the bolt.
If the bolts do need to be cut, they should be cut as close to the bush as possible to allow the arm to then be removed without the remaining section of bolt getting held in position. This is the reason for not advising to simply cut the head and nut off with an angle grinder, as the short remaining section of bolt left, will be sufficient to prevent the arm from dropping away from the crossmember. Drilling may be needed in extreme cases to remove the seized bolt.
By the control arm I am assuming this is the lower arm which holds the rear spring that you are referring to. If this is the case then the spring is not a concern and will not need compressing and can be released by supporting the weight of the vehicle on axle stands, and then using a jack below the arm to take the pressure from the spring. Then once the lower arm fixing bolt has been removed the jack can be lowered to release the pressure on the spring.
Releasing the inner bolt first gives a more controlled release and is my preferred method, but either way this will work. In my experience the anti-roll bar link would also need renewing as these rarely undo without issue, and so cutting this off will often be the quickest option. It should also be noted that the inner bolt has a cam on the head for adjustment, and so the position of this should be checked before removal to ensure the replacement is fitted at the same point.