Jump to content

Moto Migrant

I hate my rear brakes

Recommended Posts

I'm almost ready tp throw the whole system in the trash, lol. I have a 2016 Evo 300 4T, the rear brakes have always squealed and kinda sucked. I've read all the horror stories about bleeding them so I never really had any desire to deal with it, I did get some of the copper brake goo on the back of the pads and that kinda helped the super annoying squeak, they will lock up the rear wheel so good enough. Fast forward to a week ago I finally got rear pads, opened the top of the master cylinder and tried to gently pry the pucks apart in the caliper, one is seized, the other just oozed out some fluid. Nice, time for a rebuild kit. I took it all apart (act of desperation?), cleaned it real nice, soaked the orings in soapy warm water for a bit, put it all back together but it was done. I resigned myself to not riding on this beautiful weekend, so I instead rebuilt the front forks (leaky seals beyond cleaning with film), did the clutch fix and built 2 new sections in my course, not bad I guess. 

Rear caliper rebuild kit arrived on Monday, time to do the deed. I reinstalled the old pads as this was going to be messy for sure. Cleaned up the master cylinder (didn't open it up) and started the process. Pucks in, went in smooth, added some fluid into the caliper to get air out and started the process of bleeding them. I have the caliper mounted up at about muffler height (clamped to a chair) and some wood in-between the pads. I'm starting nice and easy, bleed the top banjo bolt on the cylinder and I'm not really getting anywhere. Bleeding out of the nipple and not getting anywhere, the hose is 3ft long up and over the rear fender. Air bubbles keep coming out, where is this coming from?! Banjo bolts again, more nipple work. Still nothing and I'm on hour 2 at least. I take the caliper apart again, just to check, the pucks are moving good. Next day, back at it, using a philips screw driver to pump the cylinder, and I kinda get some feeling but a test ride reveals nothing. I try the reverse bleed now (hour 2 of this day?) and it helps a bit, some more banjo bolt bleeding and cursing and I have some ok feeling. Went for a 1hr ride and while the rear brakes work, they will not lock up the wheel and the squeal is so damn loud that everyone within a mile knows what's going on (probably because those old pads got soaked in brake fluid in this fun process). I park it as its dark. This morning no brakes, pedal to the floor. Try bleeding them off the bike, nada. I install the new pads and get some decent feeling but a test ride lets me know that the decent feeling is ****. I've now drank a bottle of wine and feeling good, otherwise I'm not happy with the brakes, this has been going on for days when I should be riding.

So what's my options, a rebuild kit for the master cylinder? I've bleed the clutch and front brake on this bike but the rear brake is like nothing I've done before. I hate it hahahaha. Thanks for reading my rant and look forward to suggestions or more drinking :)

Share this post


Link to post
Share on other sites
 

Don’t bother the rebuild kit for the m c just bite the bullet and buy a new master cylinder most bother with brakes comes from the m c 

Share this post


Link to post
Share on other sites
 
13 hours ago, technowaldo said:

Don’t bother the rebuild kit for the m c just bite the bullet and buy a new master cylinder most bother with brakes comes from the m c 

Agreed

Share this post


Link to post
Share on other sites
 
 

I've got a Ktm exc 400 & have done a rebuild on front a rear MC about 2 years ago & everything is working well, i'm just wondering how/why can a mc be trash after a few years ?  I have been thinking of buying the Beta 300 4 stroke, but have to say, this is making me ask questions of the longevity/quality of some of the major components of this bike ?

Share this post


Link to post
Share on other sites
 

Hi guys, thanks for all the info/help. My local dealer had a rebuild kit in stock, so I figured I'd try that 1st as it was pretty cheap. Then I'll go for a new mc. I've not ridden for a week now and it's starting to annoy me :)

Share this post


Link to post
Share on other sites
 
11 hours ago, eagle8 said:

I've got a Ktm exc 400 & have done a rebuild on front a rear MC about 2 years ago & everything is working well, i'm just wondering how/why can a mc be trash after a few years ?  I have been thinking of buying the Beta 300 4 stroke, but have to say, this is making me ask questions of the longevity/quality of some of the major components of this bike ?

In talking to people the info that I got was that these are kind of easily replaceable/maintenance parts, I also find it strange that they wear out so fast. But the rear brakes on Beta's have always been ok at best (2t or 4t) so don't expect KTM Brembo stopping power, the components are all very small. Other than the brakes I haven't had a problem. 

Share this post


Link to post
Share on other sites
 

No way of knowing if the mc is worn out or not without opening it up and checking the bore.

Pre 2017 has a poor outer seal so the mud getting in can accelerate wear. If replacing it fit the newer version.

  • Thanks 1

Share this post


Link to post
Share on other sites
 

Isn't the newer one (master cylinder) a braktec?  I can see that there is a replacement one in that brand available.  Wondered if this would help on the wife's bike.  Also there is an aftermarket disc, might help.  The Beta back brake is a bit wooden compared to my TRS.  I find it OK but she doesn't really press it hard enough.  We fitted Galfer pads on the front and this has improved the braking, but again a bit wooden compared to the TRS.  A friend has a late model Factory Evo and the front brake is noticeably sharper and again a braktec master.  (Std on Factory)

I like the Beta but the brakes are pants.  (That's "shorts" for the US contingent)

Edited by ChrisCH

Share this post


Link to post
Share on other sites
 

What can I say? I went through agonies on the back brake too. I tried every method anyone could come up with, and now I can't actually remember which method finally worked. However I did finally get it working and hopefully won't have to touch it again for a couple of years.

The squeal seems a bit odd. The only time I've heard them squeal is when they are wet and muddy. And that goes with the territory on a trials bike.

Share this post


Link to post
Share on other sites
 

I had to take a day or 2 off from looking at the rear brakes but today I got them to kinda work. A little gentle bleeding and cleaned up the new pads and then a bunch of copper brake goo on the back. It was enough to ride for 2hrs, the master cylinder rebuild kit will show up on Monday. I did check the rear rotor, it's not bent or warped (that I can see) but it will be the next part to be replaced after a new (if needed) master cylinder. The clutch fix, 10t front sprocket and rebuild forks had me smiling and clearing sections this afternoon so I was content :)  Thanks for all the suggestions!

Share this post


Link to post
Share on other sites
 

Hi

The brakes on my 4T are OK, and have never given any trouble. 

They are prone to binding if the pads are worn.  Once the pistons get pushed out to far to compensate for the worn pads they tend not to return properly.  I think they get slightly twisted in their bores.  New pads sort it though.

The rear is not a floating disc so check it is centralised in the calliper, so that both pistons move the same distance in use.  I had to shave a bit off the wheel bearing space to achieve this, but it is definitely better for doing so.

Stuart

Share this post


Link to post
Share on other sites
 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...