Rear Brake Master Cylinder Clevis Pin Stupidity!

[luvmy40]

Why in Hell would anyone install the clevis pin on the rear brake master cylinder with the cotter pin to the inside??!!!

 

Is there a trick or a special tool to get that cotter pin out! I tried a pair of bent needle nose pliers. That ain't happening! I'll see if a have a hook tool I can get around the back, but I'm not holding my breath.

[luvmy40]

The factory service manual is useless for this. It basically says "Remove mounting bolts, disconnect brake rod and remove master cylinder".

 

Am I going to have to disassemble the entire brake pedal assembly and remove the pedal shaft with the MC?

[cowpuc]

Now that you mention this 40,, I dont recall ever having a 1st Gen where that cotter key your talking about wasn't on the inside - I got a hunch it might be some engineers idea of a safety thing:think:.. I dont take no crap for errant cotter keys though... I would just take long needle nose, grab the cotter and wiggle it till it either came out of broke off, pull the pin and knock the remaining cotter key inside the pin out of with a drift punch if it did indeed break off...

[luvmy40]

I don't see any way to get a hold of it with anything. I tried needle nose pliers and a couple different hook tools. I can't even see it without an inspection mirror and a flashlight.

 

How tough is it to get the return spring back in place if I remove the pedal and push the pivot shaft through to pull the entire assembly off?

[camos]

Why in Hell would anyone install the clevis pin on the rear brake master cylinder with the cotter pin to the inside??!!!

 

Is there a trick or a special tool to get that cotter pin out! I tried a pair of bent needle nose pliers. That ain't happening! I'll see if a have a hook tool I can get around the back, but I'm not holding my breath.

I've never seen this part so just offering a WAG here. Is it possible to thread a piece of wire through the loop end of the cotter pin? If so then it could probably be yanked out. I guess the other thing is what about reinserting the pin when putting it all back together?

[luvmy40]

once I get that sucker out of there, it's going back in with the cotter pin to the outside!

[luvmy40]

So, I finally found the right pair of bent nose needle nosed pliers, got the wife to hold the flashlight, bit my tongue just right and managed to get that pesky cotter pin out and removed the clevis pin from the brake actuator rod!

 

YAY ME!

 

Then I pulled the rear brake line, removed the MC mounting bolts and lifted the MC straight up off the actuating rod. Leaving the rod right it was. That pin never needed to come out!

 

[luvmy40]

The good news is my master cylinder is now rebuilt. The bad news is I found that at least part of my brake problem was the short hose that connects to the steel line running to the front end is badly in need of replacement and will have to be fabricated as it is not available anywhere I could find.

[ChiefGunner]

So, I finally found the right pair of bent nose needle nosed pliers, got the wife to hold the flashlight, bit my tongue just right and managed to get that pesky cotter pin out and removed the clevis pin from the brake actuator rod!

 

YAY ME!

 

Then I pulled the rear brake line, removed the MC mounting bolts and lifted the MC straight up off the actuating rod. Leaving the rod right it was. That pin never needed to come out!

 

 

You do realize that your success was TOTALLY reliant on HOW you positioned your tongue, right??

[luvmy40]

What a nightmare getting that little tiny hose made!

 

None of the shops that used to make brake hoses do anymore. There were three hydraulics shops and two brake shops within rock throwing distance of me that made brake hoses all the time, 15 years ago(the last time I needed to have a brake hose made). The brake shops are both gone and none of the hydraulic shops make anything for DOT 3 systems at all now.

 

I wound up getting a 7" SS braided line from Drag Specialties, a 10mm banjo fitting from the same supplier and a brass flare fitting from AZ. I had to cut the original flare nut off and re flare with a 3/8"x24 nut to match the flare adapter from AZ as we did not have a 10mmx1.0 flare female to 3/8"x24 male adapter.

 

It's all back together now and just waiting for me to eat lunch and go bleed the system. More fun for me!

[luvmy40]

Ah, the best laid plans of mice and men soon will go awry.

 

My newly rebuilt rear MC is leaking brake fluid from the piston. I had a devil of time getting the new seal on the new piston. I must have torn it somehow.

 

Back off she comes!

[s.tyler58]

Ah, the best laid plans of mice and men soon will go awry.

 

My newly rebuilt rear MC is leaking brake fluid from the piston. I had a devil of time getting the new seal on the new piston. I must have torn it somehow.

 

Back off she comes!

 

Sounds alot like when I repair anything on my 83! If it isn't done twice, it isn't done right! Bunches of folks on here tell me as I'm telling you, "Think of how experienced you've become in a year!"

 

I repaired my anti-dive units last week and thought I was being smart to improve the ride by cutting the PVC spacers down to 5/8" from the 2" ones that were in there. NOT ENOUGH PRE-LOAD! (She drove really well after adding 11 lbs of pressure to the forks and I got almost 500 miles in two days) but tomorrow I get to tear it apart and put in newly cut 1 1/4" spacers.

 

DOH!

[cimmer]

Use some new clean brake fluid to help lube the seal and piston when you put it on.. it will help in preventing a tear or nick happening to it..

 

Rick F.

[7 lakes]

I would suggest assembling with actual brake system assembly fluid, it will lube things really well but will not absorb moisture from the atmosphere like brake fluid, if you slather everything with brake fluid in the open you're introducing moisture into the fluid and to the inside of your system.

 

Tim

[bongobobny]

Yup, without proper lubrication it is very easy to scarf a rubber seal or o ring! Years of aircraft hardware assembly taught me this...

 

Also, did you hone the cylinder before rebuilding?? Also, check for a nasty score on the surface that can allow for fluid to blow by...

[luvmy40]

The seal was installed backwards the first time around. I know I checked it but, backwards it was!

 

I did not "hone" the cylinder as I don't have a hone that small. I did clean it thoroughly with brake fluid and a scotch bright pad and inspect it for damage.

 

It's all back together correctly and bled out with no leaks. The beast stops as well as it rolls now. I used a vac pump and fluid trap to bleed. I do think I've still got a bit of air trapped at that high point on the linked calipers metering valve but the pedal is firm enough and the braking power is as good as it has ever been(not bad) so it can wait until I have to take the fairing off for something else.

[bongobobny]

Great!!!

 

PS I've done that exact same thing once (maybe twice)...

[cowpuc]

The seal was installed backwards the first time around. I know I checked it but, backwards it was!

 

I did not "hone" the cylinder as I don't have a hone that small. I did clean it thoroughly with brake fluid and a scotch bright pad and inspect it for damage.

 

It's all back together correctly and bled out with no leaks. The beast stops as well as it rolls now. I used a vac pump and fluid trap to bleed. I do think I've still got a bit of air trapped at that high point on the linked calipers metering valve but the pedal is firm enough and the braking power is as good as it has ever been(not bad) so it can wait until I have to take the fairing off for something else.

 

IMHO,,, no need to remove the fairing and bleeding off the metering valve only takes second... Here's how I'd do it if it were mine: