Big T
Well-Known Member
On the advice of THEFERMANATOR, I went ahead and installed the Service Bulletin recommended upgraded proportioning valve (Part #12548265) on my '99 Suburban. This proportion valve is supposed to cut off pressure to the rear wheels at 800 psi, versus the 600 psi of the original valve. At the same time, I followed THEFERMANATOR's advice and installed a set of larger rear brake cylinders from the K3500 dually of the same era trucks. At $4.95 per cylinder might as well because I'd be bleeding the entire system anyway.
The job was not that hard. The proportioning valve is held in place by 3 torx bolts and of course I stripped one. I ended up pulling the entire ABS pump and just grinding through the old proportioning valve behind the bolt head. Got a replacement torx bolt free from the local bone yard.
Getting the rear brakes back together was a bit of a bear. The parking brake cable had slipped out of the driver's side and you really need 3 hands to hold the end of the cable in a pair of vice grips, while pulling the spring back with another pair of vice grips and then installing the parking brake lever assembly. Got it? Eventually I did.
I have forever had problems with the ABS on this truck. On, off, mostly off with the ABS dash light on. I'll note that the PO had it disconnected when I bought it. I've replace the front bearings. I've replaced the sensors. I recently had the right front bearing fail and that is new. Well the ABS light turned off last Sunday and it has stayed off since this work. Not sure if it had anything to do with removal of all the wire plugs on the pump or what, but the light has stayed off for at least 20+ starts now and that has never happened. The ABS actually works. I've done some testing with the brakes yesterday and today. Even had my son independently test them to verify that the brakes stop better and they do. Today, with no traffic I did some two footed stops from 60 mph and the brakes performed substantially better. I can honestly say that this was definitely an improvement and a worthwhile modification.
So on a day we give thanks, I would like to thank THEFERMANATOR for all of his advice and encouragement on this matter. That said, I still plan on doing the conversion to get the later model dual piston calipers on the front. You can never go wrong with bigger and better brakes.:Justwait2:
The job was not that hard. The proportioning valve is held in place by 3 torx bolts and of course I stripped one. I ended up pulling the entire ABS pump and just grinding through the old proportioning valve behind the bolt head. Got a replacement torx bolt free from the local bone yard.
Getting the rear brakes back together was a bit of a bear. The parking brake cable had slipped out of the driver's side and you really need 3 hands to hold the end of the cable in a pair of vice grips, while pulling the spring back with another pair of vice grips and then installing the parking brake lever assembly. Got it? Eventually I did.
I have forever had problems with the ABS on this truck. On, off, mostly off with the ABS dash light on. I'll note that the PO had it disconnected when I bought it. I've replace the front bearings. I've replaced the sensors. I recently had the right front bearing fail and that is new. Well the ABS light turned off last Sunday and it has stayed off since this work. Not sure if it had anything to do with removal of all the wire plugs on the pump or what, but the light has stayed off for at least 20+ starts now and that has never happened. The ABS actually works. I've done some testing with the brakes yesterday and today. Even had my son independently test them to verify that the brakes stop better and they do. Today, with no traffic I did some two footed stops from 60 mph and the brakes performed substantially better. I can honestly say that this was definitely an improvement and a worthwhile modification.
So on a day we give thanks, I would like to thank THEFERMANATOR for all of his advice and encouragement on this matter. That said, I still plan on doing the conversion to get the later model dual piston calipers on the front. You can never go wrong with bigger and better brakes.:Justwait2:
