View Full Version : TR4/4A Front Suspension

Frank Canale
06-14-2019, 10:08 PM
I decided to upgrade the front suspension on my TR3a with pieces from a TR4A. I am starting to see what hardware that is missing or needs to be replaced. I am using super pro bushings and am trying to decide if I need to use the cup shaped washers (Moss calls it a [shield, water]). Most of these washers have suffered from years of rust. Any experience with the new polyurethane bushings, opinions or suggestions are appreciated. Frank

06-15-2019, 05:44 PM
The TR3 and TR4A front suspensions are very different. Just what parts are you expecting to interchange?

Frank Canale
06-16-2019, 09:15 AM
Hi Charlie, I am changing to a TR4A front suspension. I am changing the upper and lower control arms, using Super Pro suspension bushings, upper ball joint, the vertical link, trunnion, brake mounting bracket, and the lower spring pan. The TR3A steering arm will be reused. This swap also lowers the front so a spring spacer will need to be added to the top of the spring . the spacer will be determined once the car is assembled (a long way off). The TR4A components are much stronger. With this swap you have the advantage of the 3 degree trunnion. The trunnion is also mounted to the lower control arms with a bolt that makes future maintenance easier. The brake mount will accept the modern 4 piston Toyota brake calipers as well as larger brake pads. My project is a complete frame off restoration and so while repairing the frame I decided to upgrade the front suspension. I am sure I have left out some details about this upgrade but it is a work in progress. Any questions are welcome. Frank

Frank Canale
06-26-2019, 10:36 AM
I have magnafluxed the vertical links to check for cracks and happily none were found. The frame is back on the welding table and is level. I have assembled front suspension parts minus front springs to start checking for any binding. Suspension goes up and down freely and the vertical links rotate smoothly. With no weight on the frame I have +2 degrees camber (suspension compressed) and +4 degrees camber (suspension extended). Both sides are exactly the same. The service manual list the camber at 2 degrees. The suspension extended camber looks to be going the wrong way. Service manual list full rebound at 1 degree. Do I need to be worried about this till I get the frame weighted and see how it looks then? Any advice is appreciated. Frank