Hello!

Here in Sweden we need to have cars inspected every year and one of the things they test are of course the brakes. Normal two wheel drive cars they run through a test equipment that first test the front wheels by slowly turning them and the test personnel press the brake pedal and thus get a measurement on how the brakes works. After that they drive the car forward a bit and do the same with the rear wheels.

But AWD/4WD cars are usually only tested outside the building with the test person just using the brakes in order to assess the brakes. For instance the 2004 Toyota RAV4 we had before as well as the 2001 Jeep Grand Cherokee we have now as well as otherwise one might severely damage the transmission/transfer case by turning the wheels on one axle when the other two wheels are stationary....

But now when I had our CX-9 tested I saw that the station test person was to runt the car through this test bed and I ran up to him and told him it was an AWD car (they have only sold a few handfuls of these cars here's in Sweden so I thought he was unfamiliar with the model) but he said that Mazda Sweden had approved this test according to his computer system...

He told me to jump in and we went over to the test rig and he tried the front axle but quickly aborted the test as he said he could "feel it was not good" for the car...! So he did just a few test brakes outside the building instead.

I have asked my local Mazda repair shop to investigate this and just got some text (in English) back from Mazda Sweden where there were some procedures described what to do to reset some systems if you was forced to do something similar:
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When only the front or rear wheels are rotated on a chassis dynamometer or equivalent, the DSC/RSC HU/CM determines that there is a malfunction in the DSC/RSC and illuminates the following lights:

― ABS warning light

― Brake system warning light

― DSC indicator light

• If the above lights are illuminated, dismount the vehicle from the chassis dynamometer and turn the ignition switch to the LOCK position. Then, turn the ignition switch back to the ON position, run the vehicle at 10 km/h or more and verify that the warning lights go out. In this case, a DTC will be stored in the memory. Clear the DTC from the memory by following the memory clearing procedure [DSC] in the on-board diagnostic system.
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But it actually does not say anything in regards to if it is recommended or not to actually do a brake test like this... Anyone here that knows?

Thanks!
Rikard

 

A assume they were using a brake roller tester?

At my old shop we had a roller tester, we drove the CX-9s on with the front wheels, immediately placed it in neutral & turned off the ignition, the rollers would come up to speed, we would press the brake pedal, get a reading & immediately start the engine & drive forward to roll the rears onto the rollers.

If we didn't do this the AWD would throw a tantrum.

My new shop has a " Safe T Stop" tester. All electronic, no rollers.

 

Hello, I do not remember if they put it in neutral or not but the engine is running at least... I will investigate if they put it in neutral or not...

The test bed looks like the one in the photo I am attaching.

What do you think, should one avoid this type of brake testing on a AWD CX-9?

Regards,
Rikard

 

It's better to avoid brake rollers for a AWD Mazda.