bleeding front brakes after install

[robgusto]

I have an 81 GS 750L and have recently put on a used set of front brakes. I had to manually push in the pistons with a c clamp to get them on the rotors. What is the process to rebuild the brake pressure? I topped off the master cylinder but I'm not able to get the brake pressure back. when I squeeze the handle there is no pressure.

[DanTheMan]

If you had brake pressure before you installed the pads, you can regain the pressure without bleeding by pumping the brake handle. If you've replaced the calipers themselves and/or broken apart the hydraulic lines you need to bleed the master cylinder first, then the splitter, then the individual calipers.

Anytime you install new brake pads the pistons have to be compressed into their bore to make room for the new pads to fit at the rotors.

[BassCliff]

Hi,

One of these days I'm going to pick up a MityVac. Until then, I do it the old fashioned way. Have a look at this: Bleeding the Brakes


Thank you for your indulgence,

BassCliff

[robgusto]

thanks

Thanks for the info I will keep trying. Nothing else seems to be working, no matter how much I squeeze the brake handle it never moves any fluid out of the master cylinder? I will try to clamp the handle down overnight to see if that works.

[BassCliff]

Hi,

There's a small return passage in the master cylinder that has to be clear. You may need to disassemble and clean it.


Thank you for your indulgence,

BassCliff

[robgusto]

thanks

I think it is the master cylinder. I took the line off the full master cylinder and I got just a drop or two of fluid while pumping the handle. There must be something caught in the master cylinder. I will be taking it apart this weekend. Thanks for the tip!

[jknappsax]

Which Mityvac are people using?

I read their product descriptions, and really couldn't figure out which kit is the one to get. Also didn't see any prices listed.

[Runningdog]

I've got a MV8000...they seem to run about $28-32 in the US. Has a guage, but I don't think the guage really adds anything to bleeding bike brakes, so maybe one of their cheaper kits would be just as useful.

[koolaid_kid]

The gauge is useful to check for leaks. It will show you if it can hold the vacuum or not.
I used a plastic MV for a while, but the cheap plastic gauge broke off, which is apparently a common occurrence. Purchased the metal MV8500, no more issues. Plus it is rebuildable. The metal pump from Harbor Freight is also a nice unit.

[Tim Tom]

If you had brake pressure before you installed the pads, you can regain the pressure without bleeding by pumping the brake handle. If you've replaced the calipers themselves and/or broken apart the hydraulic lines you need to bleed the master cylinder first, then the splitter, then the individual calipers.

Anytime you install new brake pads the pistons have to be compressed into their bore to make room for the new pads to fit at the rotors.

I know how to bleed the calipers. But where are the nipples for the master cylinder and the splitter? How do you bleed them? I didn't see anything about them in Basscliff's write up.

[cowboyup3371]

You bleed the master cylinder by pressing in on the piston, IIRC. Yep, check this page out on Basscliff's site:

http://members.dslextreme.com/users/bikecliff/images/brakes_odds-n-ends.html#A02