CRG Brakes help

mtbikerbob

mtbikerbob

Member
I bought a CRG kart that has been in storage for about 10 years. From what I have been able to determine they are VEN99 (can anyone explain what that means?). While the brakes actuate properly and there doesn't seem to be leaks, I am concerned their age may present a problem in use, O-rings and seals don't last forever. I plan to flush with new fluid but wondering if I should be doing something else. Any ideas?

Thanks for your input.
Bob
 
When you flush the brakes make sure you use the proper fluid. Most take a Dot5 fluid. Once they are flushed and you have the air out sit in the kart and apply pressure for 5min on and off and see what happens. Push on it hard. If the seals or orings are bad you will find out quick.
 
Almost all Euro karts spec DOT 3 here. The only brake systems that use DOT 5 are the MCP versions that most American and dirt karts use.
 
Seems that there are some differences in opinion. I have a fresh container of Redline DOT 4 I was going to use. Redline claims compatibility (blendable) with DOT3 and DOT 5.1. Thoughts on that?
 
If they claim they will mix, I'd be OK with it.
Won't run dot-5 in my car because of it's inability to let bubbles rise to the top, and it is almost impossible with a car's long lines, to get all the air out.
The good thing about dot-5, is that it doesn't absorb moisture from the air, like dot-3.
 
Look on the master cylinder for markings. CRG uses DOT 4 on the Ven 05 system which is the next generation and it's marked right on the master cyl. If you're not sure call a CRG dealer.
 
Scrad said:
The CRG takes DOT 3 fluid. Don't put 5 in there. It will eat the seals.
Click to expand...

I have lived in Europe most of my life till 2000 and it is even hard to find DOT3 overseas. You'll find DOT 4 that is or was the common one used there for cars or other. Never saw DOT 3 used on a kart there.
 
I have a second kart with MoGo brakes as the same VEN99 design. However, this set had no fluid in it. I have disassembled the caliper and found evidence of corrosion and pitting on the caliper piston slides. I am considering trying to hone the surface and hope there is enough for the seals to do their job. The other option is to replace the whole set up, but some shopping shows this to be VERY expensive. However I found the there is a dual piston Brembo P32F used on motorcycles that looks like might wrk some modification. Does anyone have input on either option?
 
I've heard of the Brembo motorcycle caliper, but don't know what model it is for sure. I'd try to hone the old one and try it. If it doesn't work just get the cast MCP caliper setup and make or buy a bracket for the caliper.
 
Usually pitting is too deep for honing to be effective even if the pitting is light. Sometimes the pitting is only outside the seal area and you can clean it up and use it. Also honing leaves a fairly rough surface and the bore needs to be very smooth. Best caliper I ever saw was a 1990 Dap with a brass lined bore.
 
The CRG brake systems perform great, if you can repair the one you have, worth doing.
If it's not reperabile, MCP brakes are very effective and inexpensive. An original CRG set is going to cost you some coin.

Fluid wise, I've always opted for DOT 3/4 glycol based "racing" fluids that will mix with everyday 3/4 fluids without a reaction. Specifically I use RBF600 when I can. At the same time I've used plain ole DOT3 off the shelf at autozone.
It's important to note that higher DOT ratings are not necessarily "better" In karts, we put comparatively less stress on the system and fluids.

The most important thing to remember about fluids is to never mix fluid types.

DOT 3/4 are glycol
DOT 5 is silcone

You must NEVER mix these or use one in a system that contained the other without totally flushing it, or ideally replacing the seals.

Here's how to figure out what's in your system already, personally I would never assume a system that say DOT5 on the cap has DOT5 in there:
https://forums.kartpulse.com/t/dete...in-your-kart-brake-system-before-bleeding/749
 
Dot 5.1 brake fluid is not silicone based and should not be mixed with Dot 5.0 as indicated on your kartpulse link above. Might need to do more research and change your info. Of course, I could always be incorrect but I doubt it.
 
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