Bleeding Brakes....

[Yamaha 179]

I am having trouble bleeding the rear brake on the Spondon TZ.  It is a 1980 model, monoshock, with Spondon calipers that are similar to Grimeca's.  Both the front and rear systems are original to the bike which I have owned since the early '80s.  I replaced the rear master cylinder because the original, make unknown, failed.  I bought a replacement from Vintage Brake upon recommendation by Michael (based on caliper piston size) and cannot get the brake to work.  I think it is a improperly bled system because the unusual lay-
out of the brake line and orientation of the master cylinder.  I saw somewhere, I think on the Forum, a device that was designed for changing the lube in outboard motor lower units that forced the oil, and in this case, brake fluid up from the lower brake caliper through the lines and into the master cylinder.  I searched for brake topics and then checked every thread in the general Category that had any mention of brakes in the subject line but could find nothing.  Does anyone know anything about any such device?  I really want to get this bike onto the track and while the front brake works very well the rider would like to have both of them working. 
Lyn Garland

[Evans Ward]

Lyn, I recently bought a reverse brake bleeder off Amazon for $60 after replacement of my rear master cylinder on my RZ350 to a new OEM one. I could not for the life of me get that master to bleed the conventional way no matter what I tried!  I can say without a doubt it was a great purchase and did the job perfectly! I'm going to use it this weekend to do all four calipers on an automotive application since Im replacing all the lines on a 21 yr old Jeep Grand Cherokee. Comes with lots of attachments too.

[1976RD400C]

https://www.harborfreight.com/gear-oil-and-fluid-pump-61746.html?cid=paid_google|||61746&utm_source=bing&utm_medium=cpc&utm_campaign=&utm_content=&msclkid=c4817b1976b91f536ccf25ed0e95769c

Something like this if you want something cheap and most auto parts store have.  Just take that fitting off the end of the hose and connect hose to the caliper bleeder. Stick it in the bottle of brake fluid. Pump away until you see the level rising in the reservoir. Pushing from the bottom up works every time.

[Yamaha 179]

Guys:
Thanks very much for the info.  I'll go by Harbor Freight today and see if I can pick up one of those items and I'll check out Amazon too.
I'll report back on my results.
Lyn

[bitzz]

I use a LARGE syringe, used in animal husbandry


And MOST of the time I remove the brake system from the bike and bleed it on the bench.

[85RZwade]

I've had good luck with a big syringe too.

[oxford]

I also use the large syringe through the bleeder screw on the caliper.  A second syringe is useful to take fluid out of the master as needed.  I also take the bleeder screw out before hand and give it a few wraps with Teflon tape.  This will help seal the threads while the bleeder is open and prevent air from entering.

[forexer]

https://www.harborfreight.com/gear-oil-and-fluid-pump-61746.html?cid=paid_google|||61746&utm_source=bing&utm_medium=cpc&utm_campaign=&utm_content=&msclkid=c4817b1976b91f536ccf25ed0e95769c

Something like this if you want something cheap and most auto parts store have.  Just take that fitting off the end of the hose and connect hose to the caliper bleeder. Stick it in the bottle of brake fluid. Pump away until you see the level rising in the reservoir. Pushing from the bottom up works every time.

Lyn - I had the exact same problem trying to get my rear rebuilt brake master to build up pressure doing it the conventional way. However, TSW Member 1976RD400C recommended the harbor freight pump and it worked perfectly. That guy really knows his stuff

[Yamaha 179]

Interim Report:
I ordered the reverse bleeder from Amazon and bought the Pittsburgh pressure pump from Harbor Freight.  When comparing the Pittsburgh unit to the brake bleed valve on the caliper I thought there was no way that I could get an effective seal between the large hose and the small bleed valve.  The Amazon reverse bleeder has an adapter that fits the brake bleed fitting perfectly and it took me longer to set up the unit, purge the air from it, and connect it to the caliper.  With my trusty helper mechanic (wife) watching for the fluid to be expelled into the reservoir it took about six squeezes on the handle to purge the system of air bubbles.  Hold the handle closed, remove the line, tighten the bleed fitting and you are done. 

Except in my case.  No more brake than before.  Sooo, the problem is either a poorly rebuilt caliper or maybe the M/C is the wrong size.  The brake pads are moving, just not very far.  On one occasion, early on, I used a RD front M/C to activate the rear brake (took the Brembo out of the system) and it worked fine.  That is why I thought I had an air pocket in the line someplace. 

Thanks for everyone's advice; not I go back to work...
Lyn