LBCwanabe 

I put some 700x42c tires and flat bars on my 1000 today. I also changed the chain and RD.

I notice the front drivers side left brake isn’t springing/pulling as much as the right. they are mc70 Shimano and stock afaik. Is this most likely an issue with the spring? Are there other model brakes that have compatible springs? should I just invest in some new brakes?
Thanks!

70sSanO

It all depends on how much you like them... and setting them up. You can get MC-70 brakes for $20 on eBay and pirate the spring and have some extra parts for the future.

Or you can get a set of Tektro's, or better, in aluminum and use V-Brake pads which are easy to setup.

I'm not anti-vintage cantilevers as I still have them on one of my bikes and I haven't been able to bring myself around to update them.

John

branko_76 

Have you taken the brakes apart, cleaned, relubed and properly adjusted them?

LBCwanabe 

I can’t seem to figure out how to adjust the tension on the springs?

branko_76 

mechanicmatt

Those are actually some of the best canti's you can buy. If spring tension is bad, you can see adjuster screw on one side to adjust? That should adjust for side to side tension. If it is truly weak, you may have a broken spring or you may just need to pull the brakes off clean everything everywhere and put it all back together. If it still seems weak it could just be a spring that's lost some of its tension. Take the brakes completely off and hopefully the brake post have three little spring holes on them simply move the cantilever spring to the next hole and you should have more tension on the brake. You still may have to do that on both sides so that it pulls back properly.

If you just want new, Tektro 720's are cheap and awesome.

Can you show some pics looking at the brakes?

LBCwanabe 

So I took off both sides and inspected. Tightened post bolts snug by hand and one half turn w/ wrench and issue is fixed. The post only has one hole in the middle position. All parts were well lubed. Even the black pads. Is that normal?
Thanks for the help all

LBCwanabe 

mechanicmatt

Pretty bike. So it's working okay now?

Shouldn't be lube on the pad. Use a cleaner like simple green and wipe off.

Piff 

Did you find this bike NOS? It looks impeccable.

RiddleOfSteel

That 1000 (frame) looks to be in such lovely shape! If I learned anything, it was that 700C x 42mm tires fit (astounding!), and likely with fenders!

LBCwanabe 

I wrote pad but meant bushing

mechanicmatt

Bushing can be oily/greasy. That is a ok. 👍🏻

So is it working ok?

LBCwanabe 

madpogue 

Front wheel is not centered in the fork. Double-check seating of each side of the axle in the dropouts. If it's fully seated, and still off-center, flip the wheel around and re-mount, and again be sure it's fully seated. If the off-center switches to be too close to the left blade, then the rim is not centered between the hub faces, and you re-center it by adjusting spokes. If it's still off-center in the same manner, then the fork is likely bent. Fortunately, since it's steel, a capable shop should be able to straighten it.

+1 above, on the bike overall. Time capsule bike. Do you prefer friction mode? I actually like indexed thumbies.






(LOL "driver's side"....)

ThermionicScott 

Are those pads original or cheap new ones? Some Kool-Stops could make a big difference in braking power.

prairiepedaler

Hi, does the 1000 have removable / replaceable canti stud bosses?

The Golden Boy 

My M1000LT is a 1990 and they're not. I have 5 other bikes with canti/U-brake bosses from 84-87, and they all have fixed bosses.

The Golden Boy 

The MC-70s don't have an adjustment screw- much like the older DC cantis- you just have to bend the spring to increase/decrease tension. (even the on the later brakes like the M732 and MT-62, only the left side had a tension screw)

M732MT62Bottom by Dave The Golden Boy, on Flickr



I've read of problems with the Tektro 720s on older bikes with narrower stud spacing- not just for 700c conversions- just using 27s and 720s. bikemig

prairiepedaler

Ah yes, ok... tnxs. It seems to be the fate of all bikes of this era. I have often wondered when common implementation of replaceables came into being. All the bikes I own have fixed mounts. I've shimmed mine up to eliminate excessive wear play using thin brass.

The Golden Boy 

I can't think of "wear" being a whole lot of issue with canti studs. I see studs and bosses get damaged- but I don't see canti studs worn from use.

clubman 

Interesting thought. As brakes are applied, maybe a 'squish' spot would slowly develop in the bushing surface opposite the directional force of the cable pull. Is that even a thing?
No educated opinion here but I do know that's a nice bike. So many...

The Golden Boy 

Exactly. The brake rotates on the stud on a bushing- that *should* be lubed. Even then, I assume that bikes that are not "cheap" have bosses made of hardened steel; the same with the bushings. The wear of rotating shouldn't be an issue- and the stopping force shouldn't deform either a decently made boss or brake bushing...

Unless it's more of a problem that I know of...

Salamandrine 

I've never seen or heard of a worn out cantilever post. I'd go so far as to say it doesn't happen. The brass bushing inside the canti caliper would wear out first if anything, and even that is a non issue in practice. I don't remember the reasoning behind non permanent posts. I'd imagine it was so they could be replaced if damaged in a crash. Not sure how useful that really is. May have made production easier. That seems more likely to me.

For older style cantilever brakes with no centering adjustment, like GB says, you adjust them by pulling the offending caliper back enough to bend the spring slightly. Centering can also be tweaked slightly by fiddling with the straddle and straddle wire. If it's off center, the adjustment will be off center too.

Don't forget the obvious. Make sure the wheel is dished properly, and the fork and frame is aligned. IOW the rim needs to be centered first. For post type pads, make sure that the pad posts are adjusted evenly on both sides.

madpogue 

Off-center wheel was noted on 05/05, post # 15