633CSI front end work

[newbeammer]

Just bought an 84 633csi. It has a bad vibration in the front end when braking. I haven't had time yet to get the front-end up and the wheels off to look at the brakes and the front steering components. I did try rocking the wheels side ways and there seemed to be some wheel bearing play. Any info on what to be looking for would be helpful. This is my first bmw, but I do have mechanical experience. So far I like the car.

[KC Ron Carter]

The tire bounces and the suspension is weak and just keeps bouncing.

The pulsations are most likely the thrust arm bushings.
OE was rubber and if sags it can cause the steering wheel to pulse 2 inches on brake application. Most use eurothane bushings that never need replaced. BMW came out with the 750i bushings requiring the installer to grind the bushing down to fit the e24.
Here is a link to Paul Gray, Grunt, who makes a replacement for this bad deal.

http://www.gruntsbushings.com/index.html
Bad:

Thrust arms with new bushings installed.



There is also the steering gearbox mount.
The horizontal bolts have never been an issue.

BMW has done two recalls on the vertical bolts to replace them and inspect the loop mount. They know about it but will not pay to fix it.
The BMW fix is a new engine cradle.

The issue on the loop mount was that it had to move when the steering was at maximum deflection. The gear box is not square to the steering link so when at full throw the mount needs to move to compensate.
Many owners tried to make it rigid and the mount would fail again.

Here is a link to a Dallas site that has done many welded repairs, and he has redone those same repaired mounts.

http://www.teamdfl.com/bmw/e28/front.../subframe.html

I make and sell a kit to fix this issue, and yes I have shipped many to England.

$31 US to the USA and $32 US to the UK.



The purpose of the large skin washer is to provide friction on the bottom of the engine cradle. The mount must be able to move and the washer and torque provide the need retention.
What my kit does is move the load from the loop mount to the upper and lower side of the engine cradle. Even with the loop mount gone I have seen cars with my kit go for over 30k with no issues.
I did increase the nut torque to 30 foot lbs on a few to correct for larger tires.
The black iron fitting, was an adoption since I need a bell shaped spacer and it needed to soft enough to grind an installation ramp on. The ramp is need for those loops not broken but deflected down.
The real deal wear and tear is when the upper and lower link bushings need replace and the steering wheel jumps 1 to 2 inches at every pavement joint.
That is the rapid movement that will fail the OE loop mount and the welded repairs.
When the loop mount breaks the steering will develop a 3 inch side to side play in the steering making it not drivable.
Later,

[newbeammer]

[quote=KC Ron Carter]The tire bounces and the suspension is weak and just keeps bouncing.

The pulsations are most likely the thrust arm bushings.
OE was rubber and if sags it can cause the steering wheel to pulse 2 >>

Well, I got the time to take the wheels off and check the brakes and front suspension. The brake pads had almost no wear but were frozen to the spindle. It took a srew driver and a hammer to break them loose. No wonder there was a shimmy!
I pulled the calipers and break pads off, cleaned everything up,greased the friction points between the brake pads the calipers and the spindles and put it back together. No more shimmy!
This site is so great! I have lots of other issues with electrical and so forth. The electrical schematics I've found on here and other info have been a huge help! Thanks to those that posted them!
PS. the suspension bushings looked and felt ok, but thanks for the info.