fixing(?) my UAZ's handbrakeThe handbrake on my UAZ Buhanka wasn't working. I knew about this issue when I bought it, and chocking my wheels every drive was kind of inconvenient (not to mention starting from a hill without rolling).
On these vehicles, the handbrake is a drum brake mounted directly behind the transfer case, with the drum itself being mounted to the rear driveshaft. I tested every part before the actual drum brake mechanism and it was fine.
The issue stemmed from the "разжимной механизм" , "release mechanism" (figure 11 in the image, device A-A). It's an expanding piston design, a simple but very elegant way to distribute force, but it craves constant maintenance and it's kind of a pain in the ass to get to.
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I began the process of removing it. To get the drum off in the first place, you must first remove the driveshaft. This is left up to the reader as a challenge. Make sure the vehicle is safely chocked or lifted! From this point, you can remove the two flathead screws that hold the drum on, and remove it. From this point, you can see everything, and the issue was apparent. The release mechanism was seized, extended on one side and retracted on the other! It ended up wearing down the brake shoe a little bit. You can take the shoes off and assess the damage. The shoes and springs are thankfully the same on both sides. There were two 14mm bolts on the back of the mechanism. To access one of them, the arm that actuates the mechanism (and connects to the adjuster) has to be removed fully. Remove the cotterpin and washer, and tap it out. |
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From this point, I could repack the mechanism. I took all the pieces out and cleaned the old grease off of it, finding that one of the ballbearings had somehow become dislodged inside and jammed the mechanism (hence its issues).
I noted that the fitment of a lot of the pieces wasn't the tightest anymore. There was a lot of play in the piston pieces and trying to squeeze it with my hand showed that one side wanted to move a lot more than the other.
Still, I filled the entire thing up with fresh grease... this weird bright red/pink grease. Any grease is better than no grease. This made it feel slightly better squeezing it in the hand, but the grease liked to seep out of the piston and the greasecap. I tried to tap it with a punch so it would stick shut.
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Everything got reinstalled. I ended up reusing the same shoes, hardware, and drum, since I don't live in an area where UAZ parts just fall out of trees. I tried the handle and it finally tensioned up, and I wasn't able to rotate the drum with the brake pulled. I still needed to find the perfect adjustment, since afterwards, it didn't hold on a hill and the vehicle slowly moved forward. The shoe spreader in the drum functions, so I just need to move it out some. This job took a few hours, on my side and back underneath the Buhanka, with major assistance from my dad as well. Overall, though, it was quite simple. And I'm probably going to do it again when I actually replace the release mechanism instead of just repacking it with grease. I didn't need to jack the vehicle up since it sits so high off the ground, so I laid down mats on the ground to lie on. |
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