Repairing rebushing the front subframe side mounting arms

The sub frame is attached at the front of the car by a side arm fitted each side and mounted top and bottom through captive metalastic bushes. These bushes seem fairly complex in structure and the rubber is deformable as the bushes are installed. The old bushes were in poor condition even though they hadn't actually failed and no movement was detectable at MOT. I changed the arm anyway, but thought I'd investigate what was involved in reconditioning it anyway. To press the bushes I'm making use of a 10 tonne bench press, a Draper Press and Pull kit and the odd cup from my ball joint fitting press. Even so I still needed to raid my socket set for other sizes!


Top bush

Bottom bush
New bushes, top bush (upper), bottom bush (lower)
The new top bush looks different to the old and it wasnt at first obvious how this should be mounted. Fortunately I already have one reconditioned arm ordered separately. Looking at this the orientation of the new top bush is clear.

Bush in my recon arm.

Top bushes, a recon arm is shown on the left and the old bush on the right.
The new bush needs to be inserted in this way with the "top hat" side on the flat side of the arm, the plain section then protrudes through the arm forming the stepped structure described above.
I marked the depth to which it needs to be mounted onto the new bush.
The bush was withdrawn using a Draper push and pull kit. With hindsight I can say that it is important to bear on the metal edge of the bush. Note the "stepped" metal on the side of the arm; the first of these steps (indicated with the screwdriver) is part of the arm, the second "step" is the metal case of the bush that really should be pressed. I didn't realise this and pressed on the centre of the bush.
Pressing on the centre of the bush by mistake which...
 ...which eventually pushed the insert out but...
Insert centre removed
... left the outer case in place. I had to press that out separately.
Outer case of bush- I had to press this out separately!

Using a press to remove the exterior case of the bush
I measured the depth to which the bush in my new arm had been pressed and it was 4mm. I pressed the new bush into the arm and checked the depth

New top bush in position.
The bottom bush was the same as the old so it wasn't so difficult to see how to install it. In fact the shape of the bush with a bulge in the metal casing means that it can in fact only be removed or pressed in in one way each. Again measuring the old bush showed that this was pressed in to a depth of 8.5mm. I was able to remove the bush and replace it fairly simply in the press.


Checking the depth of pressing in the bottom bush, 8mm
The new bush was relatively easily replaced.
Reconditioned arm




Comments

Post a Comment

Popular posts from this blog

Replacing the Rear Shock absorbers (shocks) and Springs

Image
Having sorted the front shocks- and made a slight improvement to the suspension noise, I decided to move on to the rears. I was also aware that corroded rear springs had appeared on the last MOT list of advisories so it was probably a good time to swap those too- although to be fair a slightly corroded spring would probably last for years! Anyway I bought two MAPCO  rear shocks 20509 with new top mounts (Sachs  802 580) as well as two Blueprint rear springs. The job is relatively simple and straightforward provided that the parts supplied are correct. Obviously you cant can't compare new to old until you have stripped the old, but you can at least make sure that the new top mounts do fit the new shocks! I failed to do this and came to regret it. The first step is to jack up the rear- although this is strictly only necessary  if you are changing the springs- you can change the shocks without raising the car! I jacked using a pad under the rear spring seat ... and
Read more

Refurbishing repairing the front lower arms (wishbones) changing renewing the bushes and balljoint.

Image
The  lower arm or wishbone has three attachment points: outboard there is the front lower ball joint, whilst inboard there is a front pivot bolt and a rear suspension joint -both secured through rubber bushes, the front is cylindrical in form and the rear a doughnut. All three are obtainable separating from a variety of manufacturers. I bought the ball-joints from Sureline and all the other bushes from Febi. This means refurbishing the arm is a cost-competitive solution and could be considered alongside complete arm replacement- certainly if only one bush has failed (usually the ball joint). However, there isn't much guidance out there for anyone wishing to go down that route so I decided to recondition my old arms. This is a summary of my experience. The process wasn't too difficult as long as you have the right tools (see below) Ball Joint I ordered new ball joints from Sureline, each joint comes with a splined press-in section and a wire clip to secure it once fitted.
Read more