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521 brakes gave up overnight


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#1 DylanLes

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Posted 10 May 2017 - 11:13 AM

Hey y'all! Bought my first 521 a couple months ago, it has all drums, been working on it a ton. The brakes needed pumping to work, So first thing I did was bleed the brake lines and adjust the brakes(thanks to the tutorial on the forum). Since then, the brakes have been running really smoothly, been driving it 4x a week about 15 miles a day. This morning I went to drive it, and my foot hit the floor. My brakes don't work at all. I emergency braked my way back home. Any idea what this could be? It just seems odd that it was so sudden.

#2 flatcat19

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Posted 10 May 2017 - 01:03 PM

Look for leaks.

You can't hang if your nuts haven't dropped...it's physics


#3 DylanLes

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Posted 10 May 2017 - 01:23 PM

There's fluid in the master cylinder still, could there still be leaks?

#4 Roadster-ka

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Posted 10 May 2017 - 02:16 PM

Did you remove the cap to check or just assume there's fluid from the stain on the reservoir?

#5 flatcat19

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Posted 10 May 2017 - 02:27 PM

There's fluid in the master cylinder still, could there still be leaks?



Is this the extent of your diagnosis?

You can't hang if your nuts haven't dropped...it's physics


#6 kelowg

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Posted 10 May 2017 - 03:07 PM

Bad mc can do that. See if when u slowly pump brakes,if brakes come back. Mine would go to floor if pedal snapped up too fast. Due to bad mc parts. Converted mine to dual res mc



#7 DylanLes

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Posted 10 May 2017 - 03:22 PM

Did you remove the cap to check or just assume there's fluid from the stain on the reservoir?


I checked this morning, there is sufficient fluid in the master cylinder.

Is this the extent of your diagnosis?

The brake fluid isn't low at all, so I didn't think it was a leak. After some research it seems that I need to replace the master cylinder?

#8 DylanLes

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Posted 10 May 2017 - 03:24 PM

Bad mc can do that. See if when u slowly pump brakes,if brakes come back. Mine would go to floor if pedal snapped up too fast. Due to bad mc parts. Converted mine to dual res mc


I tried to pump them, I got nothing, it's not even spongy.

#9 kelowg

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Posted 10 May 2017 - 05:52 PM

Sounds like seals on mc spool failed



#10 skyblue

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Posted 12 May 2017 - 02:00 PM

i would also check for leaks on the wheel cylinders on all four corners.

 

also, 521 drums require adjustment pretty regularly. I had a front wheel cylinder pop out on me once because there was too much play. 



#11 racerx

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Posted 13 May 2017 - 07:34 AM

Have u checked the ground to see if there's fluid

#12 DylanLes

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Posted 19 May 2017 - 01:09 PM

Thanks y'all! My MC was shot. It was stock. Sad to not have a stock MC but I've been informed that it's better to buy them new instead of refurbished. She brakes again(for now)!

#13 skyblue

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Posted 19 May 2017 - 01:19 PM

Good stuff. I would highly recommend doing the disc brake upgrade.

#14 DylanLes

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Posted 19 May 2017 - 01:27 PM

Good stuff. I would highly recommend doing the disc brake upgrade.


I've been obsessively researching it this week. Did you follow Beebanis instructions ?

#15 skyblue

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Posted 21 May 2017 - 09:28 AM

I've been obsessively researching it this week. Did you follow Beebanis instructions ?

 

i went with the mike klotz (bluehands inc) kit. mainly because i wanted to be able to use my stock steelies. i don't think 14's fit with beebanis kit. but if you're nit running 14's then you're good.



#16 spdcrazy

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Posted 21 May 2017 - 09:57 AM

I went with beebani's disk kit, I love klotz items as well.

 

either way, the MC swap to a duel reservoir is much worth it. even if you don't swap to front disk's.

 

so next time the master goes out, you still have at least half your brakes!



#17 skyblue

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Posted 21 May 2017 - 02:33 PM

I went with beebani's disk kit, I love klotz items as well.
 
either way, the MC swap to a duel reservoir is much worth it. even if you don't swap to front disk's.
 
so next time the master goes out, you still have at least half your brakes!


Yea. That ^^