Jump to content
Joeearl450

I just put new master cylinder and all new brake set with calipers also. I’m lost on how to get the new ones working. My last never worked. Any help on bleeding or something?

Recommended Posts

New complete brake system with master cylinder and all. Can’t get the cylinders to start moving. Any help much appreciated. 

Share this post


Link to post
Share on other sites
 

Welcome to the forum , from your name would guess you have a TRX450 ?? 

 

Did you put new wheel cylinders ? Does the brake lever get hard ?

 

Pinch the brake hose a couple of inches from the master cylinder with a pair of hose pinchers or a pair of vise grips with something around the teeth of the pliers to not damage the hose and see if it gets hard when you pump the lever ----does it get hard ? 

 

either you got air in the system , the wheel cylinders are frozen or out of adjustment 

Share this post


Link to post
Share on other sites
 

Yes I replaced all cylinders and master cylinders. I probably messed up by tearing it all down at one time a couple days before parts came in and doing it all at one time. I can’t get the lever to pressure up. I obviously have a ton of air. I will try pinching line to be sure it’s not a defect in the master cylinder once I get off work. Haven’t thought about that. How would I get that much air out the quickest way without a vacuum?

Share this post


Link to post
Share on other sites
 

Pinch the hose , pump it once or twice and the lever should be hard , then while holding the lever in ,  release the pinch , this will send a shot of fluid down the hose , then re-pinch again and keep repeating the process , eventually you will get it bleed , I find it helps to have two pinchers , pinch on side off at the tee so you are only doing one side at a time , does that all make any sense 

 

Make sure the brakes are adjusted properly before starting to bleed 

 

Share this post


Link to post
Share on other sites
 

Thanks man! That makes perfect sense. I’ll try that this afternoon. Appreciate the info! I’m new to the group but it is awesome  getting help this way instead of researching for hours and coming up just as lost as I was beginning. 

  • Like 1

Share this post


Link to post
Share on other sites
 
14 minutes ago, Joeearl450 said:

Thanks man! That makes perfect sense. I’ll try that this afternoon. Appreciate the info! I’m new to the group but it is awesome  getting help this way instead of researching for hours and coming up just as lost as I was beginning. 

 

Good deal , so what year and model you got  ----   

Share this post


Link to post
Share on other sites
 

Foreman 450 es. 03 model I picked up a few months ago. Got it on a deal but it hadn’t  been rode a few years. New carb and battery got it running. Still got some things to work on. No cracked plastic. Replaced a few bearings and put a seat cover on it. Have a brand new top end on my shop table. These brakes, stupid question but as I pump and hold do I release bleeder valve? Or do I put cap on master cylinder? Or what. 

Share this post


Link to post
Share on other sites
 
6 minutes ago, Joeearl450 said:

Foreman 450 es. 03 model I picked up a few months ago. Got it on a deal but it hadn’t  been rode a few years. New carb and battery got it running. Still got some things to work on. No cracked plastic. Replaced a few bearings and put a seat cover on it. Have a brand new top end on my shop table. These brakes, stupid question but as I pump and hold do I release bleeder valve? Or do I put cap on master cylinder? Or what. 

Yes open the bleeder screw while the lever is pulled in , you really need another person , I can do it by myself , but it is a long reach ,you don't have to put the cap back on , just don't let it run dry   ---- so the lever gets hard when pinched ? 

Share this post


Link to post
Share on other sites
 

It gets hard when pinched. Then I’d hold it. Release pincher and loosen bleeder on right side. Then repeat and repeat. It had a little pressure but it’s like I lost it. It pressures good with line pinched but won’t build pressure without line pinched. Left side cylinders are moving but right side stopped moving. 

  • Like 1

Share this post


Link to post
Share on other sites
 

Use a second set of pliers and pinch off the left side at the tee under the fender , so your only doing one side at a time  ---- did you adjust the brake shoes ?  

Share this post


Link to post
Share on other sites
 
14 hours ago, Joeearl450 said:

It gets hard when pinched. Then I’d hold it. Release pincher and loosen bleeder on right side. Then repeat and repeat. It had a little pressure but it’s like I lost it. It pressures good with line pinched but won’t build pressure without line pinched. Left side cylinders are moving but right side stopped moving. 

You riding yet ??? 

Share this post


Link to post
Share on other sites
 

gonna say you have air in the lines ?, or..your master cylinder needs to be rebuilt ?.

Share this post


Link to post
Share on other sites
 
Posted (edited)

I don’t use the pinch method

 

i use 3 feet of plastic hose for each brake hub—gotta fit snug on the bleed nipple. Press a hose end over each bleed nipple. Key is that brake fluid has to stay in the hose to prevent air from getting back in past the nipple. So route both hoses up from the bleed nipple, up and over the A-Arm and then down into an oil pan.

 

get those brake shoes adjusted so you know they’ll contact the hubs. 
 

Remove the black rubber puck from inside bottom of the master cylinder. Use rags to Get that master clean cylinder —don’t let any sludge go down into the lines. Make sure the piston fluid supply and relief ports are clear. I use shop rags and plumbers flux brushes to remove all the sludge.

 

i use a whole bottle of fluid to flush the lines. Just keep the master cylinder reservoir full. Start with the brake furthest from you—if you are less than 6 feet tall, you most likely cannot do this next step by yourself. 

 

Squeeze front brake lever and keep pressure on it, slightly open a bleed nipple to relieve pressure and close bleed nipple before the lever goes fully to the handlebar. If system is empty your lever may go to the bar several times while you chase out the air. Repeat until you’re getting clean fluid at each bleed nipple. you should start to build good pressure.

 

residual air is always going to try to rise in the line—it actually gets trapped in the bow of the hose just behind the master cylinder. adjust the hose and maybe handlebar slightly to get air to move directly to the master cylinder. Careful keep that master cylinder fluid from spilling 

 

jiggle the brake lever and you’ll see bubbles rising from the master cylinder relief port. 


once you have good pressure, readjust the brake shoes.

 

if the brake fluid Was really dirty, I will let the new fluid stand overnight and then reflush the system. 

B7DF8C55-E2B9-41D6-A6DC-F8DB506F557A.jpeg

A0867147-61F7-41DA-9645-3717907EC700.jpeg

Edited by Goober
  • Like 2

Share this post


Link to post
Share on other sites
 

I use the tubing and an old bottle.  Haven't ever removed the puck though.

 

There have been successes and failures by simply zip tying the brake lever back and leaving it for a day or two.  Air comes up through the MC that way....sometimes. 

 

Doesn't work all the time though.

  • Like 2

Share this post


Link to post
Share on other sites
 

the first was i did, on my project bike  was when i put the brake banjo pressure switch in, i did the pinch deal, that worked for me, the second time (fluid change) i did it like goober did.... that one worked better for me, but simplified  that change, i took both front tires off.... lol! 

  • Like 1

Share this post


Link to post
Share on other sites
 

Thanks Guys!! I will try these this weekend when I put my lift kit on. Will let you guys know the result. Y’all sure look out for a fellow! Thanks again for all the advice. 

  • Like 1

Share this post


Link to post
Share on other sites
 

 A couple of other bleeding methods , a vacuum pump and a bleeder cup and you can suction the fluid thru the system , this works ok and easy to do by yourself  ------   reverse flow I find it messy but will work  , connect a large hyperdermic needle to the bleeder with a rubber hose , fill the needle with brake fluid , open the bleeder and back flow the fluid up and thru the master cylinder , 

 

image.png

Share this post


Link to post
Share on other sites
 
6 hours ago, jeepwm69 said:

simply zip tying the brake lever back and leaving it for a day or two.  Air comes up through the MC that way....sometimes. 

 

i used a bungie cord wrapped around both the lever, and grip, and a hose on the bleeders to collect the fluid.... but this bring me to another point, after i changed the fluid the brakes worked better, go figure.. the reason was the banjo switch wasn't working like it should, now i can barely apply the front brakes and the brake light comes on. 

Share this post


Link to post
Share on other sites
 
On 8/10/2021 at 10:57 AM, Fishfiles said:

You riding yet ??? 

I finally got a little time to fool with it today. Besides I’ve been riding without brakes my whole life. 😂 makes those hills harder to go down tho. Here’s what I got.  If I pinch right or left side off at the t the open side is braking perfect. Brake lever has plenty pressure. But...without one side or the other clamped, my lever is very very weak on pressure. Any advice? 

  • Like 1

Share this post


Link to post
Share on other sites
 

Sounds like you still have some air in it 

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...