Rebuild brakes

[zalle]

Hey guys, I bought kits to rebuild front and back brakes on my 79Z, including cylinders.

I would like some guidance and tips for the job. Including what type of grease and oil.

Thanks

[Larry Zimmer]

Essentially, for an external joints/sliding surfaces, use a silicone brake grease. Don't get any on the pad friction surfaces. NEVER on any internal parts such as pistons and seals. To lubricate the seals and pistons use brake fluid. I would recommend DOT 4. DO NOT use DOT 5 anywhere!

[daves79x]

Carefully inspect the bores of both master cylinders. If you find any pitting, that's a problem. You can hone them with a stiff bore brush hone and perhaps clear them up, but if pitting remains, you need to have the cylinders re-sleeved. Apart from that, make sure all the seal grooves are clean and free of the white powdery residue. A Dremmel with a wire wheel works great, as well as the Scotchbrite ball Dremmel has. Then be absolutely sure both tiny fluid return holes in the master cylinders are clear. I assume you are installing new brake lines as well?

I'd invest in a Mity-Vac brake bleeder also. Even then, the front system takes forever to bleed.

Dave

Dave

[NobleHops]

I have converted to using “red Rubber Grease” instead of brake fluid for assembly of brake pistons and seals, and also adopted a sealant for the bleed screw threads in place of the Teflon I formerly used.

The sliding pins and their wells are very critical for proper function. I suggest those be carefully cleaned out including with a spray of brake cleaner, and test for fit before lubing them. I had to lightly hone a set recently to keep the pins from sticking and binding. I’m using a Permatex ceramic brake parts lubricant these days. As Larry said, keep all lubes away from the pad surface.

If the pads are good but grimy, hose them down with brake cleaner spray and freshen them up on a sheet of 220 sandpaper atop a flat block or sheet of 1/4” glass.

IMG_0785.jpeg

[mrcbx]

HMMMM ... thank you Nils.......

[Larry Zimmer]

One other comment when rebuilding brakes: do not put any lube on external surfaces of any sliding components. Clean them well and keep those surfaces dry. Any external lube only serves to hold dirt and resist sliding. (Road dirt, brake pad dust, etc.) If the surfaces of any slider pins, etc. show any corrosion, replace them. A little rust goes a long way too -- in the wrong direction resisting sliding.

That Red Grease looks to be good assy stuff! Neat.

One other 'tip' I'll add when rebuilding brake calipers: a big help for getting crud out of things is to boil the calipers in water for about 20 minutes. Let ehm cool and dry. (They dry rather quickly.) It removes a lot of crud. What it doesn't remove it turns to a much easier to clean white stuff in the grooves and corners. (Thanks, Dave Ditner. RIP. Miss you, my friend)

[daves79x]

I've used the red grease for brake parts assembly. Have to say I'm not impressed. To me, it makes the master cylinder pistons somewhat 'sticky' when first introducing brake fluid to bleed the system. I'm sure it's just me, but I've gone back to just using brake fluid. The grease is good, however, for installing the front m/c cup onto the m/c, as well as the 90 degree spigot with o-ring on the rear m/c. But please - carry on!

Dave

[zalle]

Guys, fantastic tips.

I need some eye surgery today, and I will be off 3 weeks at least. Will proceed after that.

Did the stupid thing of riding a motorbike without eye protection, and a bug or a stone hit my eye and made a tear on my retina... Be careful guys.

[Larry Zimmer]

Damn!!! Good luck with the surgery.

[zalle]

Hi again, 10 days after surgery, and looking at the floor 24/7, doctor says I'm ok, so I'll tackle this again.

Do dismantle them, should I take oil first, or take them off the bike with oil, and remove it later?

[CBX-tras]

Remove as much fluid as you can, prior to disassembly.

Additionally, if you still have the stock lines, now would be a great time to upgrade to stainless braided lines.

[zalle]

I have the stainless steel ones.
Thanks

[zalle]

Here we go... Rear break disassembled. A couple of rusty parts need powder coat, OR zinc plate? What do you think?

[daves79x]

Your rebuild kit may or may not come with the plunger rod. The brake spindle is yellow zinc. Check the caliper piston carefully for pitting. If you find any, it's junk. Check the m/c bore carefully for pitting. Hone the cylinder with a brush hone and if there is still visible pitting, you'll need to re-sleeve it. Otherwise, suit yourself cosmetically to what extent you want to go.

Dave

[zalle]

IMG_20240305_191206.jpg

Front brakes off.

I will also replace the brake light switch, that never worked (at least in the 30 years I've had it )