'81 Interstate rear brakes

[D-50Dave]

The problem with one clip is I'm missing material at the inner "notch". I'll try your suggestion for treating the rotor. Thanx, Dave

 

[D-50Dave]

Went to the local dealership on the off chance they had a set of clips on some dusty back shelf; no go. The owner (a friend I rode the school bus with in grade school) thought I might be able to just reassemble without the clips. His reasoning was that the aftermarket pads had less need for them and that the clips really just deaden chatter. Thoughts?

 

[joedrum]

Absolutely correct in my opinion

 

[D-50Dave]

joedrum » Yesterday, 8:09 am[/url]":122hmpkq]
Absolutely correct in my opinion

Good enough for me. Moving forward this weekend.

 

[D-50Dave]

So I'm at the point of adding brake fluid and bleeding. Added fluid to the top of the reservoir, some bubbles came out the top and the level dropped 1/4-1/2 inch. Pumping does nothing, opening the bleeder at the caliper makes no difference. I've never rebuilt a caliper before, but it looked pretty straight forward. Any suggestions? Thanx, Dave

 

[pidjones]

You have to first "prime" the MC - loosen the hose connection to it and pump until fluid comes out there. Then, you can pump and bleed until the system is full and firm.

 

[D-50Dave]

Will do.

 

[joedrum]

Hmm what’s the the trick there ...put your thumb over the hole in MC where hose connects ...pump lever till you feel the suction ...take your finger off ..this shoots the air through MC and in reservoir..getting MC primed ...hook up hose ...

 

[D-50Dave]

I removed the line and no joy. I unmounted the reservoir and blew in, unsuccessfully, trying to force fluid down. Removed reservoir and blew in hose directly. (tasted terrible!) Plugged. Took MC apart and its clear when dismantled. Here's how I have the internals going in.

What have I got wrong? Thanx, Dave

 

[AApple]

Looks the correct way. Here's mine....

GLbrks1

• AApple
• Nov 30, 2013

Exploded view of Rear Master Cylinder.

Perhaps you have a feed hole inside the cylinder that is clogged?

 

[D-50Dave]

Can blow through it cleanly when empty. I'll reassemble and try to blow through before mounting.

 

[pidjones]

There is a tiny, TINY hole in there that usually gets plugged. Probably under the adapter for the reservoir line. I use an unwound guitar string in a pin vise to clear it.

 

[D-50Dave]

When I assemble the MC, it certainly looks like the rubber cap over the spring and maybe even the rubber on the plunger are between the hole of the reservoir and the bottom leading to the brake line. I removed the plastic where the reservoir hose mounts and found a second divot. It seems solid bottomed. Is it supposed to be open going somewhere?

The hole on the left is clear and goes through to the main chamber. I get the nagging feeling I've got one of the 2 pieces of rubber in the main chamber placed/oriented wrong. Does the rubber over the spring cup down to the BL or up towards the rod? Does the rubber on the central plunger float in the middle or get pushed over the metal lip in the middle to anchor it at one end? Thank you for your help and encouragement. At this point, if I could buy a new whole unit, I'd just do that instead of struggle.

 

[pidjones]

Hole on the right will have a TINY hole in the center of it. Check with a fine stiff wire like a high E guitar string.

 

[D-50Dave]

It's hard as a rock. I may have to take a drill to it! :cheeky:

 

[chilidawg]

Uh uh..... Don't drill it!!!

At worst. Use the thinnest cleaner from a torch tip cleaning kit.

https://www.ebay.com/itm/Weldcote-Metal ... SwVaNc9t0j

 

[D-50Dave]

I put the guitar string in the hand drill. I used the G string, figuring the wrapped wire would help. It unwound and then the core string went thru. The wear shadows on the inside seem to show that the rubber on the plunger is the lowest. Does the solid rubber cup go between the ball and socket of the plunger and the rod? I'm thinkin' that might be my mistake. I've been putting it between the spring and the plunger.

 

[pidjones]

Solid goes on small end of spring. Then plunger end with reeds. The piston cup goes on the back part of the piston. All cups open toward outlet. Lube it all with DOT3 to assemble.

There should be an exploded assembly drawing in the FSM.

 

[D-50Dave]

pidjones » Yesterday, 9:00 pm[/url]":7wvuubdc]
Solid goes on small end of spring. Then plunger end with reeds. The piston cup goes on the back part of the piston. All cups open toward outlet. Lube it all with DOT3 to assemble.

There should be an exploded assembly drawing in the FSM.

So, if the cup goes over the small end of the spring, how does the brake fluid get past it to get to the brake line and down to the caliper? It's "down stream" from the hole to the reservoir.

 

[pidjones]

Spring goes in first. Pushes cup, piston, etc. back when you release.