Driving on a gravel road results in my Van's brakes not doing anything when the pedal is pushed <img src="/forums/images/graemlins/scared.gif" alt="" />. Pumping the pedal brings the brake level back up again.

I bled the system and checked for leaks on the slave cylinders, nothing. Faulty master cylinder?

do you have ABS?

//bc

No ABS. The pedal goes all soft until its been pumped a few times ...

I would suspect that you do have some sort of ABS or rear wheel ABS. I didn't think Isuzu made anything that lacked ABS in one form or another post-1988. At a 1999 version, I would guess that you do have 4-wheel ABS.

Michael

My vehicle is similar to the 1st Gen Rodeo found in the USA. I'm 100% sure that there is no form of ABS on this vehicle. It has a load sensing valve system at the rear axle.

In South Africa we never upgraded to the 2nd Gen Rodeo's. Being where we are in the world and the size of our economy, Isuzu / GM thought that it would be to costly to invest in the marketing and distribution of the newer Rodeo's in SA <img src="/forums/images/graemlins/frown.gif" alt="" />

OK, that makes sense.

But, Isuzu never used a LSPV on the rear axle, except for the "1-ton" long bed, 2wd pickups (1988-ish). I don't mean to keep telling you what you do or don't have, I am just trying to clear up what is really there. For all we know, Isuzu had some parts left over. It would not be the first time. <img src="/forums/images/graemlins/smile.gif" alt="" />

Is there a sensor attached to the top of the pinion side of the differential? If it is there, it would be dead center and insert from the front side of the axle. Follow the brake lines forward. Do they meet a valve somewhere on the right side frame rail? It should have a simple electrical connector and a few brake lines coming in and out of it.

Michael

Michael

I assume the directions you are giving relates to the ABS distribution module, if I can call it that ... :S

If that is the case, my vehicle does not have it fitted. the only assembly tight above the rear axle that has a bunch of brake lines all over the place, is the LSPV assy.

LSPV are common here in South Africa, it's found on most of our smaller "budget" passenger cars all the way through to the 1-ton pick-ups. Off-course on the luxury vehicles with all their fancy electronis, this valve is absent.

I forgot to mention earlier that the brake fluid reservoir is filled to the maximum mark.

Ummm... 88? None of my Amigii have had that, and they have been 1989, 1990, and 1990.

As I recall, later first-gen Amigo vehicles came with rear-wheel ABS, though.

I'm not sure where the break is...

Randii

ok, so what do you think the gravel road has to do with it?

//bc

Because this only happens when I drive on a gravel road at speed ( aprox 90km/h / 56mph )