Replacement brake master cylinder

Hello everyone,
I recently got my '82 XJ650 Maxim on the road again after the previous owner had let it sit for a few years.

I'm only getting about 1/5th the braking I expect I should be getting from the front brake. I think I need to replace the master cylinder, but I'm not sure what to buy. I'm a collage student on a budget, so I'm not against going with used/ebay. Do I need to buy another 82 maxim master cylinder? or can I get one for a different bike? Could it be something else? Thanks for any suggestions!
-Daniel

 

R U sure U need the master cylinder not just a rebuild?
I had problem with MC as well and got a rebuild kit for $25 CDN and works like a charm.

 

The front brakes on my 82 750J weren't working all that well, either; when I got everything apart, the master cylinder appeared to be working fine. The calipers, on the other hand, are badly in need of work. That might be where your problem lies vs the master cylinder.

If you update your account to show where you're at, there might be someone close by who could give you a hand.

 

Daniel, I'm with Shogun. What is it that you are experiencing?
Doesn't stop easily, pulsing brake lever, weak stopping?
I would rebuild anything you have before replacing it unless you have pulled it apart and made the determination from parade rest.
The biggest improvement you will find in your brakes is to replace the flexible rubber lines with braided stainless lines. You will find your bike stops faster with a good firm lever. It should run you about $130 or so for new lines. Check with Chacal for current applications and rebuild kits.
Welcome to the fold.

 

Sorry for the delay in responding. Work has been crazy, and school started today. Joy.

If the bike is moving at a slow speed (less than 15mph) I can use just the front brake to stop the bike. And if the bike is moving even slower I can cause the frontend to dive if I grab the lever hard. Any faster than about 15 and I feel like I could grab it hard and it wouldn't do anything (I don't have the guts to test that, going over the handlebars just isn't my idea of fun). It seems that the caliper isnt being pressed hard enough against the rotor. No pulsing. When I changed the brake pads I did notice a small amount of brake fluid on the edge of the brake rotor. I flushed the brake fluid, and have since seen no obvious leaks.

The bike was dropped on the left side. The brake lever is quite loose. The sight window has also been replaced with epoxy. Even if the caliper does end up being the cause I still need a new MC.

 

Here they are!:

Master Cylinders:

mc1) OEM and aftermarket complete Master Cylinder Assembly, brand new units perfectly replace the originals. Contains lid, diaphram, piston assembly, and lead wires for fluid level switch (on models so equipped). Does NOT include the brake light switch, lever, or mounting hardware. Lettering and style of the cover/lid may differ from your original.

NOTE: the HCP1074 fluid level sight glass WILL fit all of these original master cylinders.


HCP3014 OEM complete Master Cylinder Assembly, brand new unit perfectly replaces your original. Comes with cover, diaphram, clamp, and piston assembly, ready to install. Hand lever, brake light switch, and mounting hardware is not included. Fits all XJ650 Maxim and Midnight Maxim models. Mounting clamp is included. 14mm piston bore, horizontally tilted down reservoir orientation, towards-the-bike-centerline fluid outlet port. NOTE: the HCP3018 master cylinder listed below will fit in the same manner and style as this cylinder, but it has a larger-capacity reservoir and piston bore.
$ 159.00




Master Cylinder Covers and Diaphrams:

OEM and replacement brake Master Cylinder Covers and Diaphrams perfectly replace your incorrect, damaged, or corroded cover perfectly. A new diaphram should be fitted whenever the original is damaged, or when the master cylinder is rebuilt.


HCP3037 OEM front master cylinder Reservoir Cover, brand new top cover plate fits and seals correctly, but no longer has the word YAMAHA in raised letters across the face. Fits all original XJ550 all models, XJ650 Maxim and Midnight Maxims, and XJ1100 front master cylinders. Each:
$ 13.00

HCP3034 OEM front master cylinder Reservoir Diaphram, brand new accordion style rubber diaphram fits and seals as original. Fits all original XJ550 all models, XJ650 Maxim and Midnight Maxims, and XJ1100 front master cylinders. Each:
$ 8.00



Master Cylinder Rebuild Kits:

mc1) OEM and aftermarket brake Master Cylinder Rebuild Kits contain all the operational parts you need to correctly rebuild your master cylinder: piston, piston seal, piston spring, piston rubber sealing boot, and retaining circlip. NOTE: the piston seal does not come pre-installed onto the piston, and at first glance, you may wonder "how the heck do you get that small seal opening over that large piston?". Well, lots of lube (brake fluid) and patience and a small, dull pry tool works wonders. Make sure that you install the seal with the flared seal "lip" facing towards the fluid outlet!

NOTE: be sure you very carefully clean and inspect your used, original master cylinder for any damage and rebuildability. If the pressed-in steel piston bore is badly scarred or pitted-rusted, then it must be honed to a silky-smooth finish before installing new components. If pits or scratches are too deep to be removed, it is best to obtain a replacement master cylinder (new or used) rather than to try to rebuild a damaged original. Remember, your life literally depends on your brakes....not always in day-to-day riding, but when it counts the most, in an emergency situation; and those always happen in the blink of an eye, and without prior warning.....

Master cylinder rebuild kits contain the piston, the piston seal, the spring, the plunger end seal, the plunger dust boot and its retaining circlip.


HCP3031 OEM front Master Cylinder REBUILD KIT, for all XJ650 Maxim and Midnight Maxim models (with single front disc brake) and all XJ1100 front master cylinders.
$ 37.00

HCP1695 Aftermarket front Master Cylinder REBUILD KIT, for all XJ650 Maxim and Midnight Maxim models (with single front disc brake) and all XJ1100 front master cylinders.
$ 30.00