I had left my 90s sitting for a long time as I didn't need to drive.

I had to replace a battery and there's also now something odd with the brake system.
Last time I let it sit for a while, first time driving, as I pulled back, brakes were dry, but after 10-15 pumps, pressure was restored.

This time, it's not coming back.

I tried bleeding the brakes and replace the master cylinder (then bleeding again).

I was able to get the driver front pretty well clear of air, but the other wheels have an unending supply of air.

The reservoir level was fine before I started fiddling with anything and has been good since - of course, me keeping it full during bleeding.

So - anyone ever have anything go wrong with the ABS or their system which would be a good next point to look at? Maybe I'm just terrible at bleeding the system which has a slow leak?

 

it could be that tubes expened. maybe you have a clog. Also does the brake pedal go all the way to the floor, or it stops somewhere in the middle?

 

Ok, I can't think of anything besides what you did, but I can tell you that there is probably nothing wrong with the ABS, it's just an electrical pump, so don't mess with it!

 

fix the slow leak then do the right work

 

At first, it was to the floor. Once I seemed to get a good bleed on the driver wheel, after the master cylinder replacement, the brake would go to the floor minus the smallest amount.
It was ALMOST to the floor. As a side note, the pedal resistance is highest within the first inch or so, there's a tight "bump" and then little to no resistance to the floor.

Any strategies for finding a brake leak? It must be slow enough that there was no puddle nor drips of brake fluid (dry time?)

Typical areas to focus on?
Having been around all the calipers, those were bone dry.
Up near the master cylinder, etc. all looked good too.

Shouldn't the reservoir drop precipitously once I pump the brakes a few if there's that much low resistance air in the tubes?

Also, I was able to get the driver wheel to look good, but the other 3 had a lot of air. Is each wheel independent or can air find its way back?