brakes never feel solid

[JasonB]

I can bleed brakes but obviously have issues with them on atv's. After bleeding the rear brakes on two seperate bikes, there is pressure but the pedal goes down a solid 2 inches before real pressure hits and the brake caliper acuates. Why do my brakes feel spongy? Do I just need to keep bleeding them or switch to braided SS lines?

[rablack21]

There are several possible causes.

#1 Brake lines may be very old and are expanding, so you are not getting the pressure to the caliper piston
#2 Brake fluid may be old. Brake fluid will only absorb so much water until it becomes spongy
#3 Master cylinder is wore out.

The first two are generally the two most common reasons. If your caliper piston seal was messed up, you would see the fluid leaking out.

[trx250scar]

It seems to me if you do not use some sort Of vacuum they never get real solid. Maybe because there is still a small amount of Air in the lines and the Air compresses easier than fluid. Just my experience

[GO OVRIT]

You could have lines swelling, but atv brakes are tricky to bleed.  I use a hand pump vacuum/pressure bleeder.  I've also taken the calipers off and moved them around some to let gravity help.

[aberegg05]

I had same prob with my fronts. I bought steel braided ones and it fixed it

[rablack21]

Jason, at the very least, if you are still using factory brake lines that are 20 plus years old, you should swap over to steel braided lines as a bare minimum. Many people have had problems with the old OEM expanding over time including myself.

[TRXforever]

I had the same issues, I bought streamline SS lines all the way around...problem solved!

[JasonB]

ya i was afraid of that! I will pump the lines with my vacuum pump and see if that fixes it. otherwise i will just over up a pair of SS lines for both the 310 and 500 i guess! Thanks for the responses, i have bled COUNTLESS cars brake systems and for some damned reason the simple short ATV brakes have always given me hell!

[rablack21]

ya i was afraid of that! I will pump the lines with my vacuum pump and see if that fixes it. otherwise i will just over up a pair of SS lines for both the 310 and 500 i guess! Thanks for the responses, i have bled COUNTLESS cars brake systems and for some damned reason the simple short ATV brakes have always given me hell!

The old brake lines are probably the reason. When I got my SS lines installed, I  have never had an issue with bleeding the brakes, and I don't use a vacuum pump either.

[pantera1975]

I ut on ASR racing lines and rebuilt the master and caliaper including the pistons and mine on both machines are soft  to me the fronts I can pull the lever to the bar but on grass or gravel it locks up same with the rears maybe the ASR lines are not that good???

[sangheraent]

I find ss lines easier to bleed then rubber lines. but none the less all atv lines are a pain in the ass for some reason.

[KASEY]

There are several possible causes.

#1 Brake lines may be very old and are expanding, so you are not getting the pressure to the caliper piston
#2 Brake fluid may be old. Brake fluid will only absorb so much water until it becomes spongy
#3 Master cylinder is wore out.

The first two are generally the two most common reasons. If your caliper piston seal was messed up, you would see the fluid leaking out.

just so you know liguids DO NOT COMPRESS,,,, you could have all water in the brakes and if its properly bled it won't be spongy!!!!  so rule out #2

[fearlessfred]

just so you know liguids DO NOT COMPRESS,,,, you could have all water in the brakes and if its properly bled it won't be spongy!!!!  so rule out #2

when the water in the brake lines become heated ,it can make your brakes spongy, water is your brake fluids worst enemy

[sameltoe]

I felt the mighty vac was pulling air around the bleeder threw the threads. So I used about 4 feet of clear tubing that fit tight over the bleeder and sucked on it and cracked the bleeder. For some reason the fronts weren't to bad...but that rear took for ever on mine.