So I had to just recently change out one of the wheel cylinders on my 1990 D350. Bled out the brake system according to the manual. Since finishing that a few days ago, my brake pedal is getting progressively hard to push. And just today, as I press the pedal, it is squeaking as though I am applying too much pressure, but it really isn't moving much. Where should I start? First it was spongy, and after emptying the brake fluid entirely and filling it back up and bleeding the system, it was good, but is now almost hard as a rock.

 

Probably tripped the combination valve.... And knowing they're cast iron, they can jam with rust when they do so. Probably have to take it apart and clean it out.

 

Will taking it apart and cleaning it require me to bleed the brakes again? As I can imagine that I will lose brake fluid, correct?

 

Yes, unfortunately. There's a little plunger on the front of the valve block, that supposedly can be reset, but mine have never been able to budge. YMMV.

 

Good to know. Getting late now. So probably have to tackle it tomorrow since I don't know how long this will take and having to get some more brake fluid. I'll check back in tomorrow with my progress. Thanks for the help.

 

So I got it off and cleaned it up. Definitely had rust built up in it. Went to start hooking it back up. I have to rear brake line and one of the supply lines reconnected as well as one of the front brake lines attached. Having a hell of a time reconnecting the other front brake line and the other supply lines connected. Any recommendations on how to get them on. There is no way to get it from the top.