View Full Version : Drum Brake Problems
07-26-2011, 12:38 PM
I just changed the shoes in my rear brakes on the mini. After taking it for a short drive, I found that the pedal depressed almost to the floor, and after stopping multiple times it did not get any better. After pumping it a few times, it gathers pressure and stops fine, but requires pumping on every stop.
While I was removing the shoes I noticed that some fluid escaped when the pistons were depressed too far to one side or the other. It did not leak when it was near center, so Im not sure if this is normal or not. I have yet to bleed the system, but it seems like this should not be required for a simple shoe change. I am concerned that since some fluid came out of the pistons that some air might have gotten in.
The brakes were adjusted so that I could barely get the drum back on (even scrapes while turning), but I did not adjust it again afterward (I JUST learned you could do this from the back of the drum, so this will have to wait until I get home).
This is the first time I've messed with drum brakes. Any thoughts? Sound familiar to anyone? :confused:
07-26-2011, 12:46 PM
I'd back off the star wheel adjusters a little bit, and then bleed the system well. These are two basic, no-cost steps that would make sense with your problem, before digging deeper.
You should be able to open the bleeder screw and let gravity bleed your brakes, keeping the master cylinder topped off. Catch the drips in a can and be patient.
07-26-2011, 12:46 PM
If fluid escaped from the wheel cylinders, and the reservoir was low, you could have introduced air, which would account for the soft pedal. I would bleed them and get them adjusted correctly and see how it feels.
07-26-2011, 01:15 PM
I didn't even know about gravity bleeding so Ill give it a shot this PM. I'm sans helper so this is really good to know. Reservoir was topped off before the brake change, so I dont think it could have happened there. Definitely appreciate the advice!
07-26-2011, 02:40 PM
Gravity bleeding does not work on all vehicles, and some need a gentle pump of the brakes to get the fluid going, but it has worked nicely on all my Toyotas. Start the process by siphoning the master cylinder fown to a low level with a turkey baster, refill with fresh fluid, and then open one bleeder screw at a time, letting it drip until the fluid is clear (15 minutes is usually enough, per line). Do other car tasks while the line is slowly dripping. I always hated having another person try to press the pedal just the way I'd like them to.
You don't absolutely have to siphon/refill the master, but usually it's time to change out the nasty stuff in the reservoir anyway.
07-26-2011, 03:26 PM
x2 or whatever on bleeding the system...I've never tried the gravity method...I bought a Motive bleeder that works great when you don't have a helper - I've also heard decent reviews on the speedy bleeders that let you bleed the system via pushing the pedal by yourself. Pretty sure someone once stated that they bleed their brakes themselves via the pedal by making sure the end of the tube coming off the bleeder is below the level of fresh fluid in a jar...
I agree that you would not think a pad/shoe change would result in the need to bleed the system but so far on 4 pad replacement jobs on my 80s (they love to eat front brake pads) each time has required me to bleed the system due to a mushy pedal...
Maybe I'm just doing the pad replacement wrong but there isn't that much to it :hill:
07-26-2011, 07:20 PM
i didnt read every post, but did you adjust the shoues properlly ? remove one drum, install one drum with one lug nut, and spin the drum with one desent spin. if its not tuching the drums it should spin a good spin or 2, adjust till there is slight drag. still spin-able, but about half a spin.
then remove that drum and repeat for other drum.. if you do it with both drums on, it wont adjust properlly becuase the other drum is still spining
07-26-2011, 09:51 PM
Buy some brew, grill some wings, bake some coookies, bake somthin'! Get somebody in your end of the forrest to help you BLEED YOUR BRAKES! I use a whole quart to bleed all 4 corners, and then the LSPV. You do not want to rear end the plastic in front of you.
07-26-2011, 11:34 PM
Thanks for all the advice. Got them bled out this evening using the gravity method. Much improved! Was pretty amazing all the sediment that came out of the lines. Still need to do the fronts and lspv but it should easily be ready for the weekend, and I have a few more useful skills under the belt. :beer:
07-27-2011, 08:36 AM
This isn't such an issue in Colo., but I had a Datsun with a hydraulic clutch whose fluid had absorbed so much moisture that when I pressed the clutch to the floor on a cold day, the pedal stayed on the floor!
DOT 3 (old style) brake fluid can absorb up to (I think) 5% moisture, so bleeding clutches and brakes every few years gets rid of that, too, along with the sediment you mentioned.
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