View Full Version : Ironhead Front Master cylinder
10th February 2012, 04:42
I bought a front master cylinder off eBay. I knew it was used so I bought a basic rebuild kit for it too. Few weeks after I got it I had the first opportunity to mess with it. When I opened it up it looked like brake fluid jelly inside. I haven't ever seen anything like that on any vehicle before. I guess what I would need to know is if the master cylinder is even salvagible or if I should just get a new one. If it is repairable, how should I go about it and what would cause this to happen in the first place? Thanks in advance
10th February 2012, 04:56
I'd dip it in some carb cleaner like Chemdip by Berryman are something like it.Just make sure all rubber is removed.Then I'd hit it with some emery cloth and clean the bore real good.I think it was Hopper that had a good way to do this with a wooden dowel spilit with cloth slid in groove insert and spin till bore looks so smooth if a fly lit on it he'd bust his ass.Clean with denature alcohol blow out real good and you should be good to go.
10th February 2012, 05:31
Mixing dot 3 and 5 I think makes that jelly not sure though
10th February 2012, 06:14
I've seen DOT 3 go like that. I've since switched to DOT 5.... hopefully this jelly treatment won't return for me. Jury is still out though.
To clean it up, I scraped the bulk of it out, then submerged it (minus the front brake light switch) in vinegar for 24hrs. Next, I used a dremmel tool with a small buffing wheel to clean up the bulk of what was left. Also used the emery cloth trick in the bore as suggested by Hopper. Dipped/rinsed in DOT 5 (discard the used DOT 5). Liberal use of compressed air at every step.
Re-assembled with new master cyl kit. I also cleaned up the brake line & caliper as I didn't need any DOT 3 left over in there.
Wasn't perfect when done but seemed close enough.
10th February 2012, 07:10
mine had dot 5 in it which had set for 15 years and it turned to powder :( had to get new brake lines couldn't unplug em.
10th February 2012, 07:20
Back in 1987 I was checking the fluid level in my 1983 VF750 Sabre, the bike was in the garage for the winter, which was a very cold one. The master cylinder had 'jelled' up to the point that I had to rebuild it.
10th February 2012, 07:26
All of the above mixing fluids can cause jelling and also sitting for a very long extended period of time can the cleaning suggestion.above should cover it though nothing that can't he fixed thorough cleanin and a rebuild kit should have it good as new...
10th February 2012, 18:28
would the vinegar or brake cleaner damage the chrome finish. That is a great idea about the dowel and emery cloth. I'll defiantely give that a try. I don't know how long it sat before I got it and the winter has been really mild here in Ky. I have DOT 5 in the rest of my brake system so I don't want to contaminate anything else by putting this on.
10th February 2012, 18:47
would the vinegar or brake cleaner damage the chrome finish. That is a great idea about the dowel and emery cloth. I'll defiantely give that a try. I don't know how long it sat before I got it and the winter has been really mild here in Ky. I have DOT 5 in the rest of my brake system so I don't want to contaminate anything else by putting this on.I don't think brake cleaner will hurt chrome I would plug the outlets and fill the brake cylinder let it soak then use dremel tool as was mention. Nikki
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