Brake maintenance

Good morning
Looking for advice for my rear brake system maintenance. I have a combination of MCP euro rear caliper and Italian motors brake master cylinder and is time for maintenance. Currently Is not leaking anywhere and the braided SS hose looks good.

  1. Should I only flush and replace brake fluid?
  2. New fluid & overhaul the master cylinder?
  3. Replace master cylinder (not sure how old it is)?
  4. Any other suggestion?

This is a tricky subject as the rebuild kits can be pricy but you may not have to replace all seals and o-rings. However, how long has it been since you have replaced seals and o-rings? If you don’t know or it’s been several seasons you may want to consider a complete overhaul. Leaks can be a sign but may not be the only sign they need work. Rubber can swell so while it may not leak it may not function smoothly either. Personally, every season I will disassemble the caliper and master cylinder and give they a thorough clean in my ultrasonic cleaner and usually rebuild every other season.

As for your application what fluid do you use? I had a MCP caliper that used DOT 5 silicone, make sure you use the same fluid.

I have owned this kart for 2 yrs and no history of the last rebuilt. I agree on the degradation of the o rings and maybe the fluid needs replaced (moisture or what not). For my particular master cylinder , rebuilt kit is $38 or new unit is $88, do not much of a difference ($50). As for the fluid, I am not sure, so is there a way to tell? Otherwise is a complete flush. For what I have seen is DOT 5. New pistons and o rings are $15, so not too expensive.

If it works, don’t wreck it by disassembly! Change out the fluid and carry on.

DOT3, 4, 5.1 are compatible fluids with each other. DOT5 is not compatible with those three. If your system uses DOT5 use DOT5. If it doesn’t, look for the highest wet boiling point DOT4 or DOT5.1 fluid you can find.

The thing is, I don’t know when was the last service

Since you don’t know the history I would personally rebuild everything, but that is up to you.

As for the fluid, when I had DOT5 it was tinted blue or clear, whereas traditional fluid has that golden motor oil appearance. If your fluid is old it might be discolored making it harder to tell what you got. The feel is different too but its tough to describe. I’m not sure if there is another way to tell the difference. As Charles stated you can not mix the two, DOT 5 is silicone DOT 3,4,5.1 are Glycolic Ether based.

Up to you, without knowing when or if it was last done yeah I’d replace the seals. I did it on my energy couple years ago, it’s easy peasy.

Ordering parts for both (caliper +master cylinder). The track I go to has a nice hairpin at the end of the front straight and a fence about 20-25 feet away. Not looking forward to a visit.
Thank you all for the feedback.
Stay safe!

If you are not sure on the fluid type, just put a drop of the brake fluid in some water. If it mixes its the glycol based, if not its the silicone (Dot 5.0) based. Stick with whatever you have.

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Agree 100% on Charles reply. For simple maintenance about every 3-4 track days I check the MC fluid for signs of excessive moisture and color, then gravity siphon out and refill the reservoirs with fresh fluid. Just’a FYI, some very slight moisture is common by atmosphere exposure when removing the MC caps and or kart washing. Hope this helps.