86 2WD brake question

[Deez]

I recently purchased an 86 van and went in to do the brakes, all 4 shocks and swaybar bushings. When i removed the drivers front wheel I found the caliper was frozen and had not been working for some time (rusted disk) When I pushed the caliper apart with the caliper tool I could not get new pads in, so since the brakes worked well enough before I did this I put the wheel back on and figured I would address this later. When pulling the van back out of the garage i hit the brakes and it barely stopped with what seemed like only the back brakes engaging and pedal going easily to the floor, more than it did before I touched the brakes. I've since bled the brakes twice (second time for good measure) they are only slightly better and I found the front pass side brake caliper is engaging. When the engine is off the brake pedal gets and stays stiff and has resistance, as soon as I start the engine the brake goes almost to the floor with very little resistance. I have a new drivers front caliper I got from parts geek, it's for an 87 which I read will be ok and I also got new rear drums and pads. I'm hoping this will help but I'm not confident it will return the braking back to at least as it was before. We are using the van for an art car project so it's not a daily driver but at this point it's not safe to drive this way either. Any guidance or input is greatly appreciated and needed. Also, since we have cut the van apart I have two front doors with working manual windows and a few other parts we've removed. I would be happy sell them for super cheap, I feel like its a waste to toss some of these parts. I'm in the Colorado Springs area if anyone is interested. Thanks so much for your input and advise

[Jan-Willem]

Well, if you find the definitive solution, please let me know as well
I have been fighting the bleeding of the brakes as well, I had these issues as well with a Mitsubishi Pajero, also with a similar load proportioning valve setup. This valve makes it really hard to bleed, if there is air in the system!
There are 5 bleed nipples, one at each wheel, and one at the proportioning valve. Bleeding seems to work better when the valve arm is up (like the van has a heavy load), but I still haven't gotten mine perfect either. (it is good enough, but the pedal is still not as firm as I would like, especially on slow stops)

[Deez]

Where is the proportioning vavle? I haven't bled that one, it seems like every little bit helps. Do you know where the brake booster is? I'm wondering if I might have a vacuum leak as well.

[Jan-Willem]

For the proportioning valve. On the rear
axle, left (drivers) side of the axle, you see a thin rod mounted, follow this rod forward, it is attached to the proportioning valve, mounted to the frame. It has a bleed nipple
on it.
for the brake booster, you can see it above your pedals, for access, you need
to remove the instrument cluster, which is not very difficult, just a couple of philips screws, and you have to then disconnect the electrical and speedo cable. There is a post on here about removing the dashboard, it includes pictures of the instrument cluster.

[Deez]

I did read the post about replacing the master cylinder and watched the videos related to removing the dash. It's not crazy hard looking to do but it's a bit of a process for sure. I'm going to try to put this new drivers front caliper on and change out the read drums and shoes first, they need to be done anyway. I'll keep you posted on my results. I did some reading on the proportioning vale and I think thats not my issue and most likely doesn't need to be bled.

[Jan-Willem]

There is absolutely no need to remove the entire dash to replace the master cylinder, you only need to take out the instrument cluster. 10 minute job. Then there is really plenty access to replace it.

[Deez]

Awesome Jan, thx so much for that! Now I'm way less hesitant to do that if it turns out all the other brake replacement stuff doesn't work out

[Deez]

There is absolutely no need to remove the entire dash to replace the master cylinder, you only need to take out the instrument cluster. 10 minute job. Then there is really plenty access to replace it.

I'm assuming you've replaced yours and that's how you know? Do you know how to test the brake booster? I think it would be smart to check that before I go all in on the master cylinder job. I'll do a little YouTube check on the brake booster check as well.

[Jan-Willem]

Yeah I replaced my master cylinder (not the booster), because my pedal was sinking slowly,with or without engine running. Plus its nearly 40 years old.

And my pedal was, well, actually still is, softer than I would like, with engine running. So I have never doubted my brake booster. If the brake booster or the vacuum to it would be bad, I'd expect my pedal to be too hard, rather than too soft. And the engine is running perfectly fine, braking or not, I have no reason at all to assume a leak in the vacuum system.