eric002

I have a Mongoose legde 6061N and I've been having issues with my back brakes for quite a while. Some time ago , I noticed that when I squeezed the back brakes, instead of springing back, the rear brake assembly kinda slowly eased back into place. I tried everything from replacing the pull cable to messing around with every possible tension combination. In the end I completely stripped off the rear brakes and it kind of sat there for like a month. Today I finally got around to trying to reassemble them and I noticed one thing. The left arm of the brake springs back correctly, but the right one moves back slowly to the starting position. I tired readjusting the spring tension but no go. What could be causing this? Is the spring faulty or is this something like too much grease? Do I have to find a whole new brake assembly or is there a simpler fix? Need answer ASAP

dsbrantjr

It is possible that the end of the mounting stud has gotten flared out by overtightening. It happened to me and a little judicious file work made it right. Does that brake arm slide/rotate smoothly along the stud or does it stick?

Retro Grouch 

Mongoose says "low end components" to me.

My experience has been that you can struggle with that brake (Pro-Max?) and get it to function for a period of time. It's so much easier and not much more money to simply replace it with a medium priced Shimano V-brake. That's what I would do.

leob1

Take every thing apart, take the brakes apart, clean it, reassemble with a light coat of grease, install new cable and housing. I run into this problem weekly, dirty old grease is usually the problem.

eric002

The mounting stud is fine, the arm rotates freely. I think it's the arm itself

eric002

The brake does seem a little grease clogged, but I have no idea how to take it apart. I'm not completely new to bike repair, I just can't figure how to take apart the spring assembly

eric002

This seems like the best option. But an amazon search for "Shimano V-brake" turns up several models in a pretty big price range. I'm not sure which one will fit and which one to get

Retro Grouch 

There are a lot of models and a wide price range. That's because Shimano knows how to slice the baloney really thin. The quality goes up arithmetically. The price goes up geometrically.

The good news is that they'll all fit. If it was me, I'd buy the second cheapest. That'll still be loads better than a ProMax brake.

eric002

[QUOTE=Retro Grouch;19968553

The good news is that they'll all fit. If it was me, I'd buy the second cheapest. That'll still be loads better than a ProMax brake.[/QUOTE]

Is Amazon my friend on this one?

Retro Grouch 

Don't know. My go-to source for stuff like that is Niagara Bicycle.

eric002

For brakes ive settled for shimano BR-T4000 from amazon.
And while I'm at it does anyone have any suggestions for a rear derailleur. The one that's currently on the bike is bent and wasn't all that great to start with. I'm looking at something shimano from $15 to $30

Edit: I'm looking for a 7 speed derailleur with a hanger, no direct mount.

hokiefyd 

Those T4000 brakes will be just fine. Assuming your bike has anywhere from 7 to 9 speeds in the back, an Altus M310 or an Acera M360 rear derailleur would work great. These can usually be found from $15-20. Both are available in both black and silver colors. Might as well coordinate with your new brakes, right?

eric002

Thanks for the reply. I'll look into it and see what I can find. And hey matching brands and colors always look better.

eric002

Is the Acera direct mount or do I need a hanger? If I do where would I find one for my bike

02Giant 

Does your frame use a removable hanger or is it direct mount?

eric002

My bike came with a Shimano Rd-tz 31 7speed Hub Bolt Mount Rear Derailleur that was attached directly to the hub. How would I attach a Shimano Acera to that. I'll attach an image in the next post as I don't have 10 posts yet

eric002

post

Retro Grouch 

Probably a Tourney.

Honestly, I've probably adjusted more Tourneys than any other single rear derailleur model. You aren't going to get any style points but I've found them to be perfectly functional. 7-speed simply doesn't require the precision of 9+. What are you using for a shifter? Tourney's work better with lower end shifters because they have a little "fuzzy logic" built into the indexing.

eric002

What does the Tourney have over the Acera? If I decide to upgrade my shifters should I still go with the Tourney? What would happen if I got the Acera with the current shifters I have? which are just your standard twist shifters

eric002

And one more question. My current derailleur is attached directly to the hub bolt. How would I go around attaching a different derailleur?