Hi guys, I have a question about the brake system, specifically the master cylinder, sorry in advance for the rambly post...
I drove my truck home after I bought it and the brake system is a mess. The only apparently functional brakes were on the left rear wheel, as it was locking and really touchy on the drive. On further inspection, the front brakes were totally gone (pads worn, metal-metal contact) and the steel hard lines to the rear have been replaced.
I replaced the front pads and as I pushed the caliper pistons back in to get the pads in, the rear large chamber on the master filled up with the displaced brake fluid. I then went to bleed the front brakes and couldn't get any pressure built up, even with the truck running and pumping the pedal with the bleeders open.
I figured I would change the master cylinder and started poking around on RockAuto for a replacement. It seems that there are two types- one for the 3500# axle (which I believe is the Dana 44) that has the larger reservoir in the front, and one listed for the 4500# front axle (Dana 60 I assume again) which has the larger reservior in the rear.
The MC on my truck currently has the larger reservoir in the rear, and it filled up when I pushed the caliper pistons in, so I know the front circuit is plumbed to that side.
Below is picture of my setup along with what RockAuto lists as the correct part for a 77 W200.
Does anybody know why these master cylinders are different? RockAuto lists the 3500# part as having a 1 1/8" bore, but they don't specify the bore size of the 4500# part.
I'm wondering if my erratic braking is due to the incorrect master cylinder, or maybe I just need to replace it with the same one (front circuit to rear reservoir) and see if that works.
I tend to overthink things, so if anyone has any comments, feel free to let me know!
I drove my truck home after I bought it and the brake system is a mess. The only apparently functional brakes were on the left rear wheel, as it was locking and really touchy on the drive. On further inspection, the front brakes were totally gone (pads worn, metal-metal contact) and the steel hard lines to the rear have been replaced.
I replaced the front pads and as I pushed the caliper pistons back in to get the pads in, the rear large chamber on the master filled up with the displaced brake fluid. I then went to bleed the front brakes and couldn't get any pressure built up, even with the truck running and pumping the pedal with the bleeders open.
I figured I would change the master cylinder and started poking around on RockAuto for a replacement. It seems that there are two types- one for the 3500# axle (which I believe is the Dana 44) that has the larger reservoir in the front, and one listed for the 4500# front axle (Dana 60 I assume again) which has the larger reservior in the rear.
The MC on my truck currently has the larger reservoir in the rear, and it filled up when I pushed the caliper pistons in, so I know the front circuit is plumbed to that side.
Below is picture of my setup along with what RockAuto lists as the correct part for a 77 W200.
Does anybody know why these master cylinders are different? RockAuto lists the 3500# part as having a 1 1/8" bore, but they don't specify the bore size of the 4500# part.
I'm wondering if my erratic braking is due to the incorrect master cylinder, or maybe I just need to replace it with the same one (front circuit to rear reservoir) and see if that works.
I tend to overthink things, so if anyone has any comments, feel free to let me know!
