Brake testing machine doesn't like VX??

I brought my 2001 VX in for a Missouri state safety inspection. The place only did inspections and no repair other than light bulbs. They had a brake testing machine where they drove the VX into the service bay onto this machine that looked mostly like a lift at a couple MPH and slammed on the brakes. The machine has some kind of plates under each wheel that measures the grab of the tire or something like that. It looks like a longer drive-on lift of some sort.

I have brand new rear pads (ceramic) and calipers (thanks to a leaky rear axle seal) and their machine said that the rear brakes were not working at all.

I think that due to the VX's unique suspension and traction system, the brake testing machine just can't test the VX correctly. They didn't agree but I also don't think they knew what they were talking about. Does anyone have any experience with their VX on these brake testing machines?

I brought it to another inspection facility that did a manual brake test and inspection and thought the brakes were fine. However, the original inspection station said the only way they would pass it is if it passed on their machine. I need to find some proof to show that their equipment is just not able to test the VX accurately.

Thanks

Dean68

Do they know how an ABS system is designed to work? When slamming in the brakes it prevents the brakes from locking up which is what it sounds like they were trying to get them to do.

I don't think it had to lock up the wheels in order for it to work. I think that because it was not going very fast, the front were plenty to stop it? I am not really sure exactly why, I just don't think their machine could test the VX properly. They couldn't even think outside the box at the possiblity that their machine was wrong.

Dean68
St Louis, MO

The ABS will not kick in at super-slow speeds like that.

Dean, there is nothing so special about the VX's suspension and drivetrain that brakes operate differently on it. I don't mean to take sides against you, but you should consider the possibility that their machine is right and your brand-new rear calipers were installed with air bubbles in the brake lines and are not in fact doing much squeezing (a far more likely possibility than their machine somehow not being able to test what VX tires are doing on their load sensors).

Good luck!

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Originally Posted by Dean68

Does anyone have any experience with their VX on these brake testing machines?

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I've never heard of such a machine. However, I would ask them if there is a minimum wheelbase that their machine will accept. I know for a fact that they won't run a VX on the rollers for the Colorado AIR program because of the short wheelbase and AWD. They can't get their dyno rollers close enough together to test the VX, so they do a simple 2-speed idle test instead.

So it might just be possible that the rear wheels aren't on the sensor. Also, if they really slammed on the brakes, the back end might even come off the ground, in which case it might appear to the machine that the back wheels aren't exerting any force on the plates.

I would want a second opinion from the test guys... find the one guy in the place who handles the special cases...

Just.... wow. Do you recognize ANY of those techs in this pic?

http://www.abashrine.com/circus/Aba_..._Clowns_05.jpg

When hi-tech fails miserably. Never heard of such a machine and they should know better than to rely on it like it's God's gift to brake testing. It doesn't take much to test brakes and if they rely on it that much, they clearly have no clue what they are doing with vehicles in the first place. Stick to their circus jobs. :)

Hi standard brake test machines cannot test a LSD rear axle - i just had mine tested and they used a manual machine and just drove the VX and slammed on the brakes - then applied the hand brake at 20 mph = passed no problems
cheers
Steve

I am sure that the people at the testing station had little knowledge about any of their equipment or much mechanical knowledge. It was hard to even discuss the issue with them because they were as smart as a stuck lug nut.

I don't think it is a limited slip issue because a lot of cars have that and they would have had the problem often. I ended up bringing it to another facility (one that was actually a repair shop) and they didn't find a problem and passed it. It cost me an extra $12 for a second inspection.

Thanks for everyone's comments.

Dean68

Quote:

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Originally Posted by WormGod

Just.... wow. Do you recognize ANY of those techs in this pic?

http://www.abashrine.com/circus/Aba_..._Clowns_05.jpg

When hi-tech fails miserably. Never heard of such a machine and they should know better than to rely on it like it's God's gift to brake testing. It doesn't take much to test brakes and if they rely on it that much, they clearly have no clue what they are doing with vehicles in the first place. Stick to their circus jobs. :)

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LOL...:laughgray

A kid walks up to a clown at a party, who is feverishly tweaking on a balloon.
Kid says to the clown "what are you making?"
Clown says "minimum wage." (rimshot)

AaaaaHa-ha-ha-ha-ha-ha-ha-ha-ha...:rolleyesg