"Coffee grounds" in break fluid

[Scotsman]

"Coffee grounds" in break fluid

Recently bought a TR3 that had been sitting for a number of years, and had to bleed the break fluid due to air in the lines and it came out with what looked like coffee grounds in it. Does anyone know what causes this. Also is this a symptom that suggests I should be replacing parts etc.

I replaced with Castrol dot 4 and the breaks now feel firm and appear to be working fine.

 

[hondo402000]

Re: "Coffee grounds" in break fluid

could be rust from the wheel cylinders or rubber part deteriorating

Hondo

 

[Gliderman8]

Re: "Coffee grounds" in break fluid

could be rust from the wheel cylinders or rubber part deteriorating

Hondo

I think hondo is right on. If it's been sitting, it's probably moisture collected over the years causing rust.

 

[tdskip]

Re: "Coffee grounds" in break fluid

And to answer your question, personally I'd replace the lines at a minimum at this point.

 

[Kleykamp]

Re: "Coffee grounds" in break fluid

At a bare minimum, rebuild the master cylinder, calipers and wheel cylinders and push lots of fluid through the system to clear out contaminants in the lines, prior to hooking up your rebuilt parts. Cutting corners on brakes is never a good idea.

 

[hondo402000]

Re: "Coffee grounds" in break fluid

if you get more of the coffee ground materials stick a magnet to it if it picks them up you will know its rust, if not, rubber parts, then I would replace all the hoses, maybe MC and take the wheel cylinders apart and check them out too, as far as the lines, blow compressed air thru them and that will clean the gunk out. never saw a steel line rust on the inside with all the old cars I have had as long as they had brake fluid in them, but any thing thats cast iron like MC and wheel cylinders will pit badly

Hondo

 

[Scotsman]

Re: "Coffee grounds" in break fluid

OK, I guess the take home is for me to do a complete brake system rebuild. Two questions:

Looking at the Moss Motors "breaks/hydraulics schematics", are there any parts that can safely be reused, or should I be replacing everything? For example the 5 way (Key#56) and 3 way (Key# 42) connectors, break light switch. Will happily replace if recommended but I don’t want to spend $$ if unnecessary. The plan will be to replace master cylinder, rebuild callipers and reuse reservoire unless there is good reason to replace.

Does the pipe in the Moss "break pipe Set" bend easily by hand? I know some pipe material will kink easily especially when trying to make right angle turns.

Any other tips for the novice?

 

[Andrew Mace]

Re: "Coffee grounds" in break fluid

If it were my car, I would do a thorough visual inspection of the hard lines and think about renewing any that looked well-rusted, etc. If the hoses are more than, say, 10 years old or show any signs of deterioration or damage, renew them as well. If your system seems to be functioning well (other than the "coffee grounds") and you feel confident doing so, I would consider good rebuild (seal, etc.) kits for the master cylinder, wheel cylinders and calipers IF disassembly of same shows them to be otherwise clean and the bores don't show any rust pitting or other scoring or damage. But many folks are more comfortable simply putting new cylinders on rather than rebuilding, and I appreciate that. It's just that I find some of the currently available new cylinders are simply not up to the quality of the OEM parts (IF said OEM parts are rebuildable, that is)!

 

[Scotsman]

Thanks all for your feedback. Figured out the problem. The previous owner had used rubber washers on the inside of the reservior and over time they had broken down into a sludge. Surprisingly it didn't leak. After doing some research and speaking to ERICKS Seals and Plastics (previously California Seal and Fastner), and Chinook O-Rings they both said that EPDM o-rings should be used and they work like a charm. One on the outside of the can for the break nipple, and then one on outside for clutch together with one inside between the two reservoirs. I also asked them about the Dupont - Viton o-ring washer combo used in the Moss reproductions and they stated EPDM should be used rather than Dupont Viton. Interesting!
I got 10 o-rings from Chinook O-Ring for $5.00 (minimum order). A lot cheaper than the $100 reproduction, and if the above Co's are correct more appropriate o-rings.