pwb

Hi, i need a serious answer, is it okey to do a brake test on a GC 93 ZJ with LSD where thay test the rear brake by rotating each wheel different ways?

Bustedback

Rotating by hand will not damage the LSD, but it may be difficult to do by hand. Even using the engine power won't hurt it for a short time.

pwb

But what about a machine (brake test machine)? My local jeep dealer say that they do the test on road, but that there is machine that would test a 4x4 but he wasnt sure about if it could test a car with 4x4 and LSD. Many other places didnt know that a LSD shouldnt be tested on a brake test machine.

http://www.ukmot.com/3-7.asp

"
Certain vehicles should not be tested on a roller brake tester, eg vehicles with

More than one driving axle permanently engaged

Limited-slip differential

Belt-driven transmission

Brakes for which the servo operates only when the vehicle is moving

These vehicles should be tested using a properly calibrated and maintained decelerometer or a plate brake tester designated as acceptable for the statutory tests, see Sub Section 3.7 B, page 25, and C, page 26.

A roller brake test is also not appropriate for vehicles with damaged, under-inflated or studded tyres.
"

This is from UK
http://www.motinfo.gov.uk/htdocs/m4s03000701.htm