Clutch Hydraulics Issue

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GeoffM
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Clutch Hydraulics Issue

Post by GeoffM »

Hi everyone,
While getting the roadster back on the road, I noticed the clutch pedal didn’t engage, so I did a gravity bleed. I noticed that the fluid was completely black and even after exchanging a whole can of dot3, the pedal hasn’t changed.
Also, after the pedal was depressed a few times and the fluid in the master circulated, it’s completely black again. I’m guessing the seals have deteriorated for…reasons?

Anyway, both master and slave are new-ish. Should I buy kits and rebuild them or change them out outright…again?

Thanks for any advice.
Geoff
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Re: Clutch Hydraulics Issue

Post by redroadster »

Dot 3 ,4,Brake fluid eats rubber ..slowly
The seal was dipped in brake fluid then assembled if it's old stock it's been working on the rubber for yrs
Dot 5 silicon fluid doesn't deteriate rubber BUT , If a tad of the old fluid mixes with it , it reacts to form a RTV adhesive and ruins even the lines .
Last edited by redroadster on Wed May 22, 2024 10:39 am, edited 2 times in total.
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Re: Clutch Hydraulics Issue

Post by drieseck »

Buy the kits, you'll be fine. In my experience, however, the hose was deteriorating and the culprit it was being "eaten" also. So if the components are newish, might consider it first, or with the re-build..
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GeoffM
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Re: Clutch Hydraulics Issue

Post by GeoffM »

Thanks…the hose is new-ish but I guess you never know with NOS parts. I fired the parts cannon.

Could a tight fork adjustment cause the same issue?
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Re: Clutch Hydraulics Issue

Post by Habitat.pat »

I bought a new hose , master & slave cylinder a couple years ago but didn’t get the fluid into for over a year. My fluid turned dark almost immediately. Turned out the “NEW” hose was over 15 years old! I’ve replaced the hose but haven’t filled the system, waiting on other parts but expect the fluid will not be dark.

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Re: Clutch Hydraulics Issue

Post by Solex68 »

I'm not sure why but it's common to see the clutch master cylinder reservoirs typically have the fluid turn dark. I've replaced both master and slave and experienced the same. I have even turkey basted the black fluid out and refilled it, but its fluid is still darker than the brake's reservoir's fluid.
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Re: Clutch Hydraulics Issue

Post by DAC21 »

Not much that can be done about the piston cylinder cups, but I guess the one rubber bit that can be taken out of the equation is to go to a stainless clutch hose and see what happens?? NOS Rebuild kits for Clutch Master / Slave could be 40+ years old well before Dot 4 came out. Maybe stick with Dot 3 if you rebuilt with old kits?
Last edited by DAC21 on Tue May 21, 2024 3:09 pm, edited 1 time in total.
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GeoffM
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Re: Clutch Hydraulics Issue

Post by GeoffM »

Good ideas everyone.
I might get the local shop to make up a hose for me when I swap out the cylinders and see if the hose or the cylinders are the source of the black rubber staining the fluid. The hose I have is NOS that I replaced 10 years ago. I haven’t considered that a collapsed hose could be why the slave isn’t actuating.
I guess when I replace all three items…I’ll inevitably fix the issue anyway…whatever it was. :)
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Re: Clutch Hydraulics Issue

Post by spyder »

I replaces the clutch hose with the Gates braided lines and the black went away.
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Re: Clutch Hydraulics Issue

Post by DAC21 »

spyder wrote: Tue May 21, 2024 2:58 pm I replaces the clutch hose with the Gates braided lines and the black went away.
Do you know the P/N?

TIA
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Re: Clutch Hydraulics Issue

Post by zippy67roadster »

I carry a full clutch hydraulic kit that includes the clutch master, slave cylinder and new spring and a stainless steel braided hose for the slave cylinder. You can buy them as a kit or only the parts you need. you can find them at sincitydatsuns.com
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Re: Clutch Hydraulics Issue

Post by GeoffM »

Thanks
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Re: Clutch Hydraulics Issue

Post by spyder »

DAC21 wrote: Tue May 21, 2024 3:09 pm
spyder wrote: Tue May 21, 2024 2:58 pm I replaces the clutch hose with the Gates braided lines and the black went away.
Do you know the P/N?

TIA
I picked it up in a pack that had all the brake plus the clutch hose so, sorry no.
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