John_Kreiter

So I recently bought a 1979 240d it's a running driving car but it is not free of issues the biggest right now is the brakes, they needed to be pump four to six times before they would start to work and then they would stick once they did so I thought I would try bleeding the brakes clean and replacing all the pads, this went well for the back brakes the fluid looked like bogwater with some good size bubbles in it the pads were still decently thick but just about disintegrated when handled which gave me hope that this might just be my problem, until I got to the front right brake, the fluid came clean quickly enough however there these tiny bubbles that persisted in coming out even after the fluid coming through the line cleared up, my dad who was helping me suggested a leak in the master cylinder which made sense as literally no othe visible component of the brake system had fluid on its exterior though a good portion of that was due to a lack of a funnel during bleeding. So now I'm looking into rebuild kits or new master cylinders so I can start bleeding all over.
is there any specific points in the braking system I should look into while I'm at it? I'm just checking incase something is failure prone that I didn't know about, the front calipers are ATE if it makes a difference

John_Kreiter

Alright so I dived into the brakes over the last couple of days, rebuild kits were a bit of a pain to get in but nothing extraordinary aside from the dust boots which were a royal pain to fit on I ended up having to patch one with rubber cement after picking a hole in it with the tool I was using to try and press them into place. Master cylinder install was painless though getting the reservoir onto the new cylinder was excruciating simply for fear of breaking it and having to source another. The dust boots for the fluid level sensors were cracked horribly and replacements run like $7 ish a piece so I made new ones out of 1/2" tubing by cutting a piece roughly 1" to an 1-1/2" putting it on a 1/2 inch bolt with a 1/4" or so hanging off, heat the overhang with a lighter then fold it in on itself to create a cap.
one thing to note about 1979 model year is that part way through the year they changed from 15mm thick pads to 17.5mm pads in the front I think it had something to do with them introducing ABS that year but I'm not sure, any way I found out the hard way that my car was made in January so my pads didn't fit luckily you can just by the pads for a 78' and they will fit just fine. I'm going to bleed the brakes tomorrow after work and hopefully take it for a test drive that hopefully won't be as terrifying as driving it home. Anyway here's some pictures of the work I've been doing on her

Here she is in all her half assembled glory


Drivers side caliber, on its way apart


Drivers side caliper on reassembly


New master cylinder installed


Passenger side front


Driver side front


Shot reservoir float boots


Home made float boot, its not pretty but i works which fits with the car (mostly)


Hose used to make new float boots
Other things on the to do list include; getting a new windshield installed (which I have it's just not something I can do), and the windshield wiper linkage is shot (also have a replacement for that), and some minor interior junk and some seals that are shot (have most of that) that pretty much covers it for now I'm gonna try and keep this going as best I can, haven't really done any sort of "build thread" before.