Brake bleeding question front disk rear drums (1 Viewer)

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Oct 27, 2019
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I have a dual system, originally got a leak in rear wheel cylinder, replaced all 4 with brand new now I'm bleeding the rear drums. I have blead them until there is no air, still soft pedal, blead again just to be sure, still soft pedal. I have not "set up my drums" ie: adjusted my wheel cylinders yet.... could that be the issue? I've put over 1 L of fluid through the system still soft pedal.... any advice is appreciated.
 

3_puppies

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the shoes need to be adjusted, before bleeding would have been better.
what is happening is the master can only push so much fluid and it is using all that it can move to push the wheel cylinders, but there is too much throw before the shoes contact the drum.
adjust shoes tight, back off 5 clicks or so, the shoes should drag slightly
 
Joined
Oct 27, 2019
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Grand Coulee, SK, Canada
the shoes need to be adjusted, before bleeding would have been better.
what is happening is the master can only push so much fluid and it is using all that it can move to push the wheel cylinders, but there is too much throw before the shoes contact the drum.
adjust shoes tight, back off 5 clicks or so, the shoes should drag slightly
Thank you, I just wonder why the disk brakes dont make the pedal normal regardless of what I'm doing with the rear drums, I'm new to brakes as you can tell. Thanks again
 
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Did you replace the cylinders with OEM or aftermarket. Aftermarket cylinders can allow air to get trapped causing bleeding trouble.
 
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As a quick test, you can clamp off the rear brakes at the flexible line from the chassis to the differential (using vicegrips or similar).. if you get a great pedal feel after that you'll know its the rears still causing problems. Dont drive with your rears clamped off, they'll eventually lock on.
 
Joined
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As a quick test, you can clamp off the rear brakes at the flexible line from the chassis to the differential (using vicegrips or similar).. if you get a great pedal feel after that you'll know its the rears still causing problems. Dont drive with your rears clamped off, they'll eventually lock on.
Thank you, I will give that a try, after a bunch more reading I'm starting to think I don't have the wheel cylinders tight enough, but still unsure, will report back tomorrow after work if I get some time to work on her. I do appreciate the advice a lot.
 
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Ok, so I couldnt wait, I clamped it off and indeed the pedal was much "harder" better if you will. Still think it is a wheel cylinder adjustment I need to do but it's getting late so will have to wait for tomorrow. Thanks for that tip!
 
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Still a bit spongy but thought I'd take her out for a spin at sunset.

20200715_215115.jpg
 

Pighead

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With rear wheels on and lug nuts torqued, adjust all 4 shoes out, evenly, until wheels will not turn by hand. Then check peddle feel. If acceptable, adjust shoes in, evenly, until you can turn by hand but still dragging. You can feel and hear the dragging, this is good. check peddle feel again. If acceptable, drive it. Shoes will self-clearance quickly.
Are you still using the drum brake master cylinder? did you remove the residual pressure valve for the fronts?
 
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Although I am very new here I just went through this with a rebuild of my rear drums. @3_puppies and @Pighead are correct. Also, lots of wisdom from the elder statesman @65swb45 on this topic. If you haven't yet, read through @Coolerman 's website on this job as his writeup is excellent. Actually, read through it about three or four times until everything sinks in. It is surprising how much drag is required on these rear drums in order to achieve a firm pedal. Just to add my experience on to what others have said here...be sure that both brake shoes on a single drum are equally dragging. One shoe dragging and the other one loose on the same wheel will still result in a soft pedal. It took me about four different tries at getting this right, but I eventually achieved a super firm pedal, and I can let go of the steering wheel and hit the brakes hard at 45 mph, with tons of reserve travel left, and with no veering to either side. My method, was to start my adjustment with both the shoes as far out as possible and still be able to barely push the brake drum back onto the hub. This minimizes how much work you have to do with the adjusting tool. Install the drum. Then, using the OEM adjuster tool, adjust a SINGLE cylinder outwards until the drum locks up, then back off just enough to allow the drum to spin 360 with some drag. This will probably be no more than 2-3 clicks. THEN, adjust the other cylinder on the same wheel outwards until the wheel locks up again. Then back it off the same number of clicks as the first cylinder. Your drum should now be able to turn by hand, without locking up, and with both brake shoes dragging equally. If something isn't right, take a deep breath, and start again with the first cylinder. You WILL get it right, it's a matter of feel. Repeat with the other side of the axle, and you should be good to go.
 
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What pighead said X 1000, most important is to have the rear wheel on and torqued, changes the drum more than you think, set it with drag, like enough that when you return from test drive you think the rears are hot, like he said the shoes will seat in after 3 or 4 tripsaround the block.
 
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Thanks everyone, looking forward to using all this great information tonight. Brakes are one thing that I've never took on before, still learning, the advice is much appreciated.
 
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Ok so..... giving up again for the night. I get the shoes tight, can barely turn them once torqued and still pedal goes to the floor, I pinch off soft rear brake line and pedal is hard as a rock. If I pump, it gets better but not long after (seconds) I can put it to the floor again. Going in to read more posts and that coolerman article that was mentioned. I've only owned this beaut for 8 months so most questions you have for me I may not have the answer. All I know is the brakes were working fine until the wheel cylinder leak, hence 4 new ones and this absolute mind blowing punch a hole in the wall struggle I'm having......alas....time for some beer and deep breaths. Friday shall be upon us soon, thanks guys it's nice to not be in this struggle alone!
 
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What condition is the brake master cylinder? The bleeding process allows the piston to travel down the bore further then it has in a while and can damage the seal.
 

Pighead

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I'm wondering if during your bleeding, you ran one of the reservoirs dry and got air in the master. Or, if one of the seals in the master is leaking...does the fluid in one of the reservoirs drop while the other reservoir rises? I've heard that it is possible to install new cylinders backwards, not sure how, so that the bleeder is not at the top...it's been a while since i've been into a drum brake. Can you post a pic of the orientation of your drum cylinders?
 

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