Tech Tip- 124 Parking Brake Cable

My parking brake was not returning to the stops after release, and the brake light in the dash was staying on.
This is apparently a very common problem with 124s, and searching this board, it would seem that there was a TSB regarding the Front Cable causing this problem.
It had been annoying me for 2 years, and since I have a manual tranny, it annoyed me frequently. I do not think the brake pads were actually dragging, but it never gave me a 'warm and fuzzy' feeling.

I bought a new cable for just $18 (a bargain!), and set out to replace it.

Consider Alternatives:

Upfront, I should tell everyone that if you can avoid replacing the cable, you should do so. It is a lot of work. Once I got it out, I found that my old cable had not stretched, and was in relatively good condition. It was really just binding, and the return spring was not powerful enough to overcome the friction. The cable is coated in plastic, so it does not absorb moisture and rust, like on some cars.
In retrospect, I'm quite certain I could have pulled out just the front 3 feet or so (to get gravity on my side), then poured oil down the jacket, and it would have been ok. Hindsight is 20/20...

Also, make sure cable is the problem. Cable may not be adjusted properly, spring may have come loose, and so forth...

That said, here is the procedure, front to back:

Overview:
Cable runs from parking brake pedal mechanism -> down behind accelerator pedal -> up into center console near knee -> runs under center console to the left of the shifter mechanism -> ducks through tranny tunnel near end of center console -> runs along top of tranny tunnel (over DS and center exhaust/shields) -> ends at adjustor/return spring mechanism (ahead of rear axle, over driveshaft).

Prep Steps:
1) Remove all driver's side carpet pieces, pads, styrofoam thingy, threshold trim, foot rest panel.
2) Remove center console and all that this entails (huge pain).
3) Remove center exhaust (or just the heat shield, if you can manage).

That was the hard part. The cable itself is relatively easy!

Remove Cable
1) Disconnect at a pedal mechanism (pull clip)
2) Disconnect at 3 attachment points: a) Near accelerator b) next to center console around knee height, c) under center console near rear of console.
3) Pull clip where cable jacket end clips to tranny tunnel exit hole (clip is accessed from underside (SEE NOTE at end regarding clip).
4) Remove bolt that pins cable end to adjustor mechanism. Bolt head is 11mm(surprise!).

Now cable can be pulled from inside car, easy enough...


Assembly is almost the reverse:

I took the time to pour oil (I used ATF) down the NEW cable jacket to prevent binding in the future. I just used an old fashioned trigger oil can, fed it down the pedal end with gravity on my side, and continued until oil was evident at other end.

I removed the adjustor mechanism (easy), found the pivot was binding, cleaned and lubed all moving parts with synthetic moly 'brake grease' (sta-lube).

Special NOTE regarding cable jacket clips:
The new cable (Gemo brand) did not use metal clips to secure the jacket ends. It has these built-in plastic clips with 'teeth' that simply snap in place. Metal clips are not reused.

Mistake, and bonus!:

Referencing the NEW cable, I assumed the old one had the plastic teeth as well, so I removed the cable from the tranny tunnel with (great) force, only to find that it had been solidly clipped with a metal clip. Fortunately, no damage resulted from my heavy-handedness... The good thing about this 'mistake' is that I did NOT actually have to remove the exhaust or exhaust shields to get at the clip, so I ended up saving some time and trouble here...
This is clearly not the 'right' way to do this.

Score!

Anyways, the parking brake works great now, and returns to full stop upon release.

Sometimes the 'little' things make a difference.

If you have this problem, definitely try pulling the cable just until it enters the center console, and pouring oil down the jacket. Could save a lot of work...
Alternately, I could even envision replacing the return spring with a more powerful spring...

Best of luck with your project.

__________________
1986 300E 5-Speed 240k mi.