View Full Version : Expected Rear Axle Travel
I received my FF Metal battery box today and was really excited to see the quality of the parts. When I test fit the box I became concerned that my differential cover may come in contact with the box. I've already sent a message to FF Metal, but wanted to get some input on just how much the rear axle will be moving. At full droop I have about 2-1/2" of clearance between the box and the diff cover. When I jacked the car from under the diff and from each end of the axle, it doesn't look like there is more than a 1/2" of movement. Will the 2-1/2" be enough for normal driving conditions? I also haven't set the ride height and the springs aren't compressed at all. Also, the rear should move slightly forward (away from the box) as it travels I would think.
https://farm5.staticflickr.com/4292/35840539630_e5090bd4b5_k.jpg (https://flic.kr/p/WB78Ls)
https://farm5.staticflickr.com/4322/35840537960_f9916b94e0_k.jpg (https://flic.kr/p/WB78gE)
https://farm5.staticflickr.com/4296/35840540800_cf88ad0651_k.jpg (https://flic.kr/p/WB797C)
It's always a good idea to cycle the suspension through full travel if you have any doubt. You can also chart the pinion angle change per inch of travel while you're at it. This is good info when you go to set the static pinion angle.
It's always a good idea to cycle the suspension through full travel if you have any doubt. You can also chart the pinion angle change per inch of travel while you're at it. This is good info when you go to set the static pinion angle.
What's the best way to cycle the rear? Should I disconnect the shocks and jack the axle the way I just did?
Dave Howard
07-28-2017, 10:35 PM
I have the same set up on my 2012 build. After installing the FF Metal battery box in the same location, I found out the hard way that the nice shiny diff cover will rub the battery box. To solve this, I left the battery box in the same position but removed all the attaching rivets on the front of the box. I made a spacer strip about 1.5 inches wide by the length of the box. I then pushed the front of the battery box down and secured it in place with the spacer strip. This caused the battery box to be oriented on a slight angle backwards, but provided ample room for the diff to clear the box. Once the carpet was installed in the trunk, there was no seeing that mod. Oh and I use the word mod sparingly. Buying an aftermarket kit like this isn't really a mod. You're just 'snapping' it in place. haha. The other option is to relocate the box to the front in the engine compartment. Aesthetically, that wasn't an option for me
Papa, pull the coil-overs and remove the springs. Reinstall the shocks and using a floor jack, cycle the suspension through full travel. Be sure to set the chassis on jack stands high enough to get full travel. If you have adjustable control arms ensure you have the wheelbase set correctly and get the static pinion angle close to the final setting.
Papa, pull the coil-overs and remove the springs. Reinstall the shocks and using a floor jack, cycle the suspension through full travel. Be sure to set the chassis on jack stands high enough to get full travel. If you have adjustable control arms ensure you have the wheelbase set correctly and get the static pinion angle close to the final setting.
Thank you. I know what I'll be doing tomorrow. I'm glad I didn't start cutting up the floor yet.
Dave
CraigS
07-29-2017, 06:17 AM
Be sure to set the pinion angle or your test won't mean much.