After removing front wheel, spongy brake lever

Hey guys,

Just looking for a little direction here. I removed the front wheel the other day to get the front tire replaced. I removed the brake pads and forced the caliper piston back to give myself a little more wiggle room but when I pushed the piston back I didn't open the bleeder valve. (doh).

After getting everything back reassembled I can't get the brake lever rock hard, been bleeding the thing for about 20 minutes straight now and can only get moderate pressure. When opening the bleeder valve fluid shoots out pretty far so not certain if I am just doing something wrong or I damaged something in the process.

 

When was the last time the caliper seals were replaced? Master cylinder rebuilt? Brake lines replaced?

You didn't do anything wrong when you pushed the caliper piston back without opening the bleeder.

 

I got an all new master cylinder a couple years ago but other than that, haven't... The only odd thing is I had good brake pressure before I took the wheel off

 

Well, either there's not enough fluid, something's leaking, or something's expanding. I'd bet on the 30+ year old, expired, rubber brake lines expanding.

 

I might take that bet; my money is on the 30 year old CALIPER SEALS either not sealing or not allowing the piston to move properly during re-bleeding.

NEW new master cylinder; or a different ("new" to you) one off eBay?

 

It was a new one off ebay...I rebuilt my old one and the thing wouldn't build pressure.

Yeah, I think I knew the answer to my question before I asked it. Just recently lost my job and don't want to spend too much on new parts if I don't have to. I should probably at least rebuild the caliper either way.

 

Got to. And once the caliper and master are rebuilt, the 30-year old lines are the new weak link in the system. Ever pop a brake line? I have. Not fun.

Believe me, I understand financial issues vs. the need for transportation. However, you simply can't take shortcuts when it comes to brakes. Yamaha themselves said the lines needed replacing after FOUR years. Thirty years is way beyond any safety margin that may have been designed in.

Just do the brakes right; you'll only need to rebuild them once and then they're safe. Doing it "piecemeal" keeps moving the weak link around in the system and asking for a disaster.

 

Another thought- did you tighten the axle pinch bolts last? If not your calipers and rotors aren't lined up properly. Might not be the answer but it's worth asking.

And yes, if the brake system is still original replace/rebuild.

 

Thank you for the replies, I think I will do my best to scrounge together some cash to do those three items right.

Biggs: I did tighten the nut on the end of the front axle last, what is the proper procedure for aligning the brakes with the rotor?

 

The pinch bolt is the 12mm bolt and nut at the bottom of the fork. These will be the last things to be tightened.

Seca fork.


Maxim fork.

 

If you never rebuild them, you'll be surprised what you're gonna find in your calipers when you'll open them.

MIne had some caramel-like stuff in there, beurk!!

 

Thanks for the responses guys, much appreciated.

I decided screw it, and ordered a brand new (not oem) master cylinder all together, some steel brake lines, and a caliper rebuild kit. Tired of messing around with it and getting brown brake fluid every couple months. Thing is, I'm not even the one who is riding it right now and it's one thing to take the calculated risk when it's me but if someone else got hurt on it I would feel pretty terrible.

 

:x :x :x

Grrrrr...I've spent the past two days messing around with this and finally have good braking.

I threw everything on that I purchased but for the life of me could not build brake pressure. I began by doing a bench bleed with a MityVac and couldn't build even the slightest bit of back pressure. After rebuilding the caliper, replacing the lines and MC I finally traced the issue to the MC I bought. Out of the package, bad...Guess thats what I get for trying to save a few bucks, wish I would've just ordered an OEM rebuild kit instead.