General Topics/Tech Tips Discussion on break in periods, rider comfort, seats and pad suggestions. Tech tips as they become available will be posted here.

Front MC leaking again

Thread Tools
 
Search this Thread
 
Old Feb 20, 2018 | 08:31 PM
  #1  
RANGER73's Avatar
RANGER73
Thread Starter
|
Club Member
Veteran: Army
Joined: Sep 2010
Posts: 15,420
Likes: 7,118
From: Beyond Fucital
Default Front MC leaking again

Front MC leaking again, this is twice in 5 years. Is it the DOT5 eating the seal?
94 FXSTC
 
Reply
Old Feb 20, 2018 | 09:30 PM
  #2  
98hotrodfatboy's Avatar
98hotrodfatboy
Seasoned HDF Member
15 Year Member
Liked
Loved
Top Answer: 5
Joined: Mar 2010
Posts: 21,006
Likes: 7,540
From: Poolville
Default

I don't believe so... Is not the Dot 5 a silicon based fluid... It's supposed to protect the seals... You have something else going on there.... Maybe dirt scored the plunger shaft and is slowly wearing the seal.... You live near a coast line... Salt?
 
Reply
Old Feb 21, 2018 | 02:21 AM
  #3  
Hey Man's Avatar
Hey Man
Seasoned HDF Member
10 Year Member
Liked
Loved
Community Favorite
Joined: Jun 2015
Posts: 10,276
Likes: 7,756
From: West Central FL
Default

Try changing the mc cover. Maybe you've got a bit of a warp in it. I got tired of chasing leaks on my Shovelhead and swapped out the stocker for a Nissin off a GSXR.


 

Last edited by Hey Man; Feb 21, 2018 at 02:31 AM.
Reply
Old Feb 21, 2018 | 05:29 AM
  #4  
RANGER73's Avatar
RANGER73
Thread Starter
|
Club Member
Veteran: Army
Joined: Sep 2010
Posts: 15,420
Likes: 7,118
From: Beyond Fucital
Default

It's definitely at the plunger, it doesn't squirt out (I said squirt), but more just seeps out. (Like it has a VD). Just started when I just changed out my levers. Has to be a coincidence, unless I somehow knocked the seal loose.
 
Reply
Old Feb 21, 2018 | 08:44 AM
  #5  
98hotrodfatboy's Avatar
98hotrodfatboy
Seasoned HDF Member
15 Year Member
Liked
Loved
Top Answer: 5
Joined: Mar 2010
Posts: 21,006
Likes: 7,540
From: Poolville
Default

Sounds like a complete rebuild with new plunger kit.... Time.... Sometimes just a seal will do it but sometimes it's in the shaft of the plunger... Don't forget as well, the guide for the plunger could be worn allowing the plunger to move around a little...
 

Last edited by 98hotrodfatboy; Feb 21, 2018 at 08:45 AM.
Reply
Old Feb 21, 2018 | 09:12 AM
  #6  
bustert's Avatar
bustert
Seasoned HDF Member
15 Year Member
Liked
Loved
Community Favorite
Joined: Aug 2008
Posts: 5,048
Likes: 990
Default

without looking, i assume the master is of the chevron cup type??
last change was after-market???
if so, there are a lot in you boat. i too have this issue on my 74ch. i think the issue is with the cup. the bore is clean and spec'd out so that leave the cup lip. if you think about it, all the pressure and wear is just a fraction of an inch on the cup. i do not think the cup to be too hard although it very well could be as it wouldn't take much to mess it up. the thing about glycol based fluid is it does have a tendency to soften and swell the cup where silicone does not so that too may be an issue. one thing for sure is parts ain't parts any more.
just installed a new kit in mine a few months back. on old stuff, even the hd dealer near where i live just forks over after-market crap.
 
Reply
Old Feb 21, 2018 | 03:12 PM
  #7  
RANGER73's Avatar
RANGER73
Thread Starter
|
Club Member
Veteran: Army
Joined: Sep 2010
Posts: 15,420
Likes: 7,118
From: Beyond Fucital
Default

Ya, I don’t think the controls are stock 94. The kit they sold me doesn’t match.
 
Reply
Old Feb 22, 2018 | 06:32 PM
  #8  
RANGER73's Avatar
RANGER73
Thread Starter
|
Club Member
Veteran: Army
Joined: Sep 2010
Posts: 15,420
Likes: 7,118
From: Beyond Fucital
Default

Seems to be a Drag Specialties master cylinder with a 5/8" bore. And it would seem I dislodged the plunger cap when I replaced my levers.
 
Reply
HD Forum Stories

The Best of Harley-Davidson for Lifelong Riders

story-0

8 Best Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-1

10 Worst Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-2

Killer Custom's Jail Break Is The Breakout That Refused to Blend In

 Verdad Gallardo
story-3

Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

 Verdad Gallardo
story-4

Harley-Davidson Reveals Super Cool Cafe Racer Concept

 Verdad Gallardo
story-5

Engraved Rebellion: Inside Bundnerbike's Glam Rock II

 Verdad Gallardo
story-6

10 Motorcycles You Should Never Buy

 Joe Kucinski
story-7

10 Things Harley-Davidson Needs to Fix in 2026

 Verdad Gallardo
story-8

Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider

 Verdad Gallardo
story-9

The Best and Worst Harley-Davidson Moves of 2025

 Verdad Gallardo
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ieatchickens
EVO
19
Jun 8, 2017 10:36 AM
theterribleone_vdc
Primary/Transmission/Driveline/Clutch
3
Aug 24, 2016 08:26 AM
ramu3527
Dyna Glide Models
12
Aug 3, 2012 09:42 AM
biker sean
Dyna Glide Models
4
Jun 16, 2011 08:58 AM
aposto
Wheels/Tires
6
Aug 9, 2010 07:20 PM




All times are GMT -5. The time now is 08:24 AM.

story-0
8 Best Harley-Davidson Motorcycles Ever

Slideshow: Not every Harley gets it right, but these are the ones that genuinely earned their reputation.

By Pouria Savadkouei | 2026-04-15 14:23:21


VIEW MORE
story-1
10 Worst Harley-Davidson Motorcycles Ever

Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.

By Pouria Savadkouei | 2026-04-01 20:01:09


VIEW MORE
story-2
Killer Custom's Jail Break Is The Breakout That Refused to Blend In

Slideshow: Killer Custom's "Jail Breaker" build focuses more on stance and visual aggression than mechanical overhaul.

By Verdad Gallardo | 2026-03-18 19:20:32


VIEW MORE
story-3
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.

By Verdad Gallardo | 2026-03-07 16:15:30


VIEW MORE
story-4
Harley-Davidson Reveals Super Cool Cafe Racer Concept

Slideshow: Harley-Davidson's new RMCR concept revives the café racer formula with modern hardware-and it may be exactly the reset the company needs.

By Verdad Gallardo | 2026-03-04 12:23:37


VIEW MORE
story-5
Engraved Rebellion: Inside Bundnerbike's Glam Rock II

Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.

By Verdad Gallardo | 2026-02-24 18:19:44


VIEW MORE
story-6
10 Motorcycles You Should Never Buy

Slideshow: There is no shortage of great motorcycles to buy, but we would avoid these ten.

By Joe Kucinski | 2026-02-19 14:50:51


VIEW MORE
story-7
10 Things Harley-Davidson Needs to Fix in 2026

Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.

By Verdad Gallardo | 2026-01-13 18:33:17


VIEW MORE
story-8
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider

Slideshow: Graeme Billington's left-hand-drive Shovelhead is as much about problem-solving as it is about classic Harley form.

By Verdad Gallardo | 2025-12-30 11:27:08


VIEW MORE
story-9
The Best and Worst Harley-Davidson Moves of 2025

Slideshow: A clear-eyed look at what actually worked for Harley this year, and what quietly undermined its progress.

By Verdad Gallardo | 2025-12-29 17:10:48


VIEW MORE