SYC Powersports

[Rarerat]

Tom do you by chance sell a caliper for a Yerfdog 150 spiderbox? My youngest daughters yerf's brakes quit last year and I can't for the life of me get it to work. The buggy has been just sitting in the corner but the weather is warming up so....

Today I installed new pads & bled them for about an hour and still cant get a peddle. Fluid is coming out of the bleeder with no air but still no brakes. I dont have any leak or anything that is jumping out at me, all i can think of is the caliper is bad?? Or do you have any ideas?? Funny I can build a restore a car from the ground up, but for some reason I am not smart enough to fix the brakes on my kids buggy.

[Masteryota]

I have heard this before with the Yerfs, and mine has the same issue. I think it might be the master cylinder. A few members here have reported the same mush pedal and a new master cured it. I was looking at mine last week while moving parts around, and it looks very similar to both my Suzuki rear brake masters, and I wonder if the mounts are the same. I picked up a master off ebay for less than $20 for the RM80.

[TheFauxFox]

I think mine might have a similar prob. My brake pedal is absolute mush and when I was driving it I wondered why the brakes were so weak. I told my dad "I know it's a buggy, but seriously; that's not right!" So let us know what happens here. To me I feel like its the mc cuz I've heard a ton of bad things about 'em failing and I just feel like if it were the caliper it would be blatantly obvious with something scraping, leaking or just not moving. Maybe have your daughter depress the brake pedal while you take a look around the caliper and check 4 movement?

[Masteryota]

If the caliper was suspect, it would drag and not release, or do nothing at all and have a hard pedal. If the hose was breaking down, it would either have a good pedal and not stop, or stop, and not release the pressure from the caliper. Since you have a lousy pedal, and craptastic braking, I would start with the master. I bled mine a dozen times, and got little pressure at the caliper, but no increase in stopping power. Since I was tearing it down, I did not pursue fixing it prior to disassembly.

[JERSEYDEVIL]

yea definitely the master. i replace alot of them at the shop, just sold my last one last sunday so i have to order more. but i have 2 yerfs in my arsenal and both have mine have been guilty of needing the master replaced too.

[x-bird]

nearly all the smaller dirt bike and atv calipers are 1/2 bore, same stroke. mount lugs/holes vary a little. real easy to pop apart to inspect the seal and the feed hole beneath the plastic line feed. I kept finding bits of the rubber seals from around the banjo bolts in mine. IF you don't have one, cattle syringe time Rare--they are a bit overpriced in the $1.20 range though. Flush the system and switch to copper crush washers ))) I have a caliper if you need it.

[Rarerat]

Thank you guys for the info, I replaced the line from the master to the caliper a couple of years back after the brakes locked and wouldn't release. We were out on the trails when it happened and I had to drag it out with the Odyssey with the rear brakes locked. Before I got it out the hose exploded. I replaced the line and hadn't had any problems with it until now.

When the brakes quit last year I was out in it with my 8 year old and going down a small trail with about a 3 foot deep eroded away drop off. When we got close I yelled for her too slow down. Well... long story short, she couldn't stop, she got scared and hit the gas & we launched off it & the did the ole "lawn dart" thing into the ditch. We got real lucky it wasn't a bigger drop.

I will look for a master cylinder and see what I can come up with.
Thank you again guys.

[GX150]

I always had luck with a vacuum bleeder off the caliper but others have had success with reverse bleeding the brake system. The master cylinder is too small to do it properly by pumping the pedal.

[bear]

Harbour Freight sells a bleeder kit that goes both ways!

[Rarerat]

Thank you guys.

I replaced the master cylinder, bled and flushed all the fluid again, it is starting come around, but I still think there is an issue with the caliper. They work, but not like they should.

[x-bird]

use air pressure to pop the piston out of the bore. may need a new piston seal, or there may be junk around the orifice. single or double piston?

[Rarerat]

Thanks X, it's a dual piston caliper.

[Miamieddie]

I agree with trying the bleeder kit as gx150 and bear mentioned. I was reading the same problem on buggy news that someone well many had this problem. Get a bleeder kit. At harbor freight.