Dyna Sport front brake problem
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Joined: May 2010
Posts: 58
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From: Antioch,Ca
Dyna Sport front brake problem
I have a new to me '02 FXDX (dual front disc's). The brake lever just seems to spongey to me and the lever travel to great. I would say that it's about 3/4 " of travel before I get a firm lever. May not sound like much but it sure feels like it.
I've bled the brakes twice now , once with Mity-vac once the old fashion way. No change. Could it be the Master cylinder ? Something else ? How doo you diagnose a bad MC ?
Btw there are no leaks and the correct DOT 5 fluid is in the bike
Thanks,
Rich
I've bled the brakes twice now , once with Mity-vac once the old fashion way. No change. Could it be the Master cylinder ? Something else ? How doo you diagnose a bad MC ?
Btw there are no leaks and the correct DOT 5 fluid is in the bike
Thanks,
Rich
Outstanding HDF Member
Joined: Aug 2009
Posts: 2,938
Likes: 4
From: NC
Change fluid
I have found that I have better lever feel when I keep my fluid changed. So to make it easy I empty res on handlebar by soaking it out with paper towels. Then I unbolt the line from one caliper at a time and empty caliper of old fluid. Refill caliper with new HD fluid through the brake line hole and reinstall line on caliper whil its in your hand. Now spread the brake pads and it will backbleed the line and resevoir on handlebar.(be careful to have someone watch resevior so it doesnt overfill and cover anything that may get fluid on it) Then repeat for other side. Once you have done this then you will just have to do the old pump lever a few times and hold it while you crack the bleeders a few times (2 people) and you will have a great feel at the lever. Just be patient on the dual disk setups when bleeding as they are more spongy by nature due to the extra line so they have to be bled perfect to feel good. If you arent happy with the feel after doing these steps you should upgrade to braided lines as that makes a huge improvement in feel compared to the junky OEM rubber lines. I bought braided lines immediately when I got my HD and they fixed my issues. I could pull my lever to the bar before braided lines and I can only get halfway to bar now. Hope that helps you.
Tourer
Joined: Mar 2010
Posts: 449
Likes: 1
From: The Mohawk Trail
If you've bled the brake and the master is not leaking by it's seals I'd doubt it to be the cause. Put your hand of the front rubber line when you depress the brake and see it it it swelling much. A worn out rubber line can expand causing a mushy feeling brake
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I have had my 03 FXDXT from new and the brakes have always had that spongy feel, although they work very well. One day I will get round to replacing the lines with braided ones, which I did to my Glide and transformed it, so I suggest doing that before looking any further.
Advanced
Joined: Nov 2006
Posts: 78
Likes: 1
From: SoCal
I know this is a six month old thread but I have the same brake problem on my FXDX. I would think this thing would grab right away with twin discs but not until the lever is real close to the grip. I did the bleed think twice and no change, next I think a will take the calipers off and clean them real well.
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Tourer
Joined: May 2010
Posts: 316
Likes: 2
most fxdx's I've ridden have been like this. I would say master as a culprit. You are supposed to flush brake fluid every 2 years
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Joined: Sep 2008
Posts: 4,440
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From: Northwest
Make sure you don't mix DOT4 and DOT5 fluid... that will mess you up. If you suspect of that happening... flush the entire system with something like denatured alcohol. Getting rid of the rubber-hose line and going to a harder line, will also help immensely in the feel of the brake.
I flushed my lines (with fresh, same DOT oil) at 3K miles... I got a lot of crap out of the lines... was amazed at the amount.
I flushed my lines (with fresh, same DOT oil) at 3K miles... I got a lot of crap out of the lines... was amazed at the amount.
Tourer
Joined: Apr 2011
Posts: 454
Likes: 1
From: Micawber, Manitoba
Going through old T-Sport threads, yes my T-Sport has the same spongey feel, an old HD mechanic suggests that my discs are warped. I recall several occasions of using the front brake extremely hard, enough to a point in which my front tire actually skidded on dry asphalt. No worries.