1990 C1500 ABS (RWAL) removal.

[90C1500]

I will have to give this a go on my 90. My light is flashing on the dash anyway.

 

[94Cheyenne]

94 Cheyenne needed no adapter, just went perfect. Noticeable gain of brake power/response.

 

[K15 Blazer]

wait.... my 1993 doesn't have a rear wheel unit. just a huge ABS unit... but I think it is also the proportioning unit... if I just plug the master into the distribution block the brakes will function really, really poorly...

 

[someotherguy]

Just replied in that other thread you asked in, too; your truck has 4WAL but still being 92-94 SUV you should be able to find the combo valve elsewhere - it's in there, just hiding.

Richard

 

[K15 Blazer]

its not lol

ive traced everything. distribution block, ABS, that's it. the combination valve, the thing that actually meters the master's pressure so the back end doesn't swing around, does not exist... it IS the ABS unit itself...

if I unplug it and slam the brakes at 40 mph it tracks perfectly straight.

 

[someotherguy]

On my '94 Burb with the KH 4WAL unit it had a separate combo valve. Maybe yours has some different type of setup. How about some clear pics of -yours- instead of some crummy line drawing out of a manual? Memory may be failing me a tiny bit, but I do recall specifically a combo valve on a '92 Burb parts truck w/4WAL as well.

Either way I don't see what the problem is. Understand that you need the proportioning valve. Plumb the 4WAL unit out; it doesn't matter whether your truck is 4WAL or the RWAL on the earlier pickups, you still have the same end result - a master cylinder with front/rear connections and front/rear brakes that need to be hooked to it, with a proportioning valve in between. If indeed your truck has no separate combo valve then get one off an 88-94 pickup in the boneyard and get to plumbin'!

Richard

 

[K15 Blazer]

the website is being stupid and not letting me upload anything x(

I have pics on my phone and everything but they absolutely will not upload here. that is an accurate manual drawing though.
maybe the blazers were special cause of their shorter wheel base, but, yeah... no control valve, just a junction block and that ABS thing...

 

[DRAGGIN95]

I would remove it all, and install the brake lines and prop. valve from a pickup that only had RWAL and then just do the delete on that.

 

[someotherguy]

the website is being stupid and not letting me upload anything x(

I have pics on my phone and everything but they absolutely will not upload here. that is an accurate manual drawing though.
maybe the blazers were special cause of their shorter wheel base, but, yeah... no control valve, just a junction block and that ABS thing...

I hear you; what I'm saying is all of them have a proportioning valve - it just may be that your truck has a different 4WAL unit that has it integrated, instead of separate outside of the unit. It has one, regardless of whether you can see it. So like I said and like Draggin reiterated, just get one from a RWAL truck. You need it, period, end of story - it controls how much fluid goes front/rear, your fronts get way more, that's where most of your stopping power is. It would also be good to use the factory piece so you have the combination valve that includes the brake warning light function. It is kinda redundant though; most of us don't need a light on the dash to let us know when there's been a sudden pressure loss in the braking system. We know the same time the light knows.

Richard

 

[K15 Blazer]

yeah.... the blazer is certainly tricky because of its weight and wheel base. the 80s blazers weighed less, so I couldn't really use their brake set up...

the Blazer actually has 4WAL... 2 lines out of the master to the junction block... 2 lines out of the block to the ABS pump/unit... then 3 lines out of the unit, 2 small ones direct to the front calipers and one larger line to the rear brake hose...

stopping distance is a "depends" moment lol