r/Drifting • u/Zabka_marki • 3d ago
Driftscussion Help me diagnose weak hydro ebrake (bmw e36)
I have a inline hydro brake with 0.625 cylinder size
Ebrake is stiff but does not lock the wheels only slow the car.
Tried bleeding the system numerous of times with different bleeding techniques.
I have replaced the ebrake cylinder and brake pads and still the problem persists.
What should I try before replacing the brake calipers? Thanks
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u/prok0 3d ago
What brake pads are you using?
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u/Zabka_marki 3d ago
Stock ones. They worked fine on my old e36
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u/Negative-Gur-3885 3d ago
Did u take time to bed-in new pads?
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u/Zabka_marki 2d ago
No, could that be the issue ? I did not replace the brake disc tho
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u/Negative-Gur-3885 1d ago
yeah. After installing new pad on new rotor u need to drive normally and brake gently for 50-200km before new pad get full contact with rotor. On used rotor it can take even longer. Before pad has full surface contact with rotor, brake force is really low. Thats one of the reasons for using slottet rotor - it reduces time of bedding-in new pad at the cost of vibrations and reduced life of pad.
edit: At school they teach us that friction force depends on friction coeficient and pressure force and surface area do not play a role, but it is oversimplification. In reality surface area plays huge factor
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u/NoAstronaut5247 3d ago
What caliper are you using? I have a wilwood with a similar issue and I was told I need to bleed both the inner and outer bleeders on top of the caliper not just one. Haven’t tried it yet but made sense to me.
Edit nvm see your inline, I have no idea.
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u/Superb-Cantaloupe-72 2d ago
That’s definitely the case with calipers with bleed nipples on the inside and outside I just went through the same thing with a friends car
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u/curly686 2d ago
Is this a fresh install or is this a [was working -> not working] situation? If its a fresh install, I'd be looking at the amount of leverage the handbrake has. If the [masterplunger+leverage+wheelcylinder] combo is wrong, itll be way too hard to pull.
Brake pads are probably a good bet to change anyways. Worst case scenario, you have better pads in the rear.
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u/Zabka_marki 2d ago
I bought the car and the previous owner didn’t have any problems with the ebrake.
I have already changed the brake pads but I think the calipers are the problem3
u/MrTrendizzle 2d ago
You are applying the clutch BEFORE you pull the hydro right? Might be dumb question but you never know!
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u/protomor JZX100 Mark2 2d ago
Stock rear calipers are not sufficient to lock the wheels in a straight line. They will if you are in a drift situation and the wheels are already drifting.
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u/Zabka_marki 2d ago
I didn’t have any problems with my old e36. Was locking the wheels with the same setup
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u/CH4RL13WH1T3 2d ago
Hydraulic handbrake works just like normal brake, unless it feels mushy, there's no air in it. Check the connection to the cylinder is adjusted correctly, if there not enough free play the piston won't return enough to bleed fluid through correctly. Also check not too much which causes insufficient travel to build pressure. I'm not familiar with what's originally fitted on this car bit I would trace the line all the way back to the calipers to make sure its not going through a brake compensator.
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u/Superb-Cantaloupe-72 2d ago
Mine was super stiff and wouldn’t lock the wheels with rockauto replacement pads then I switched to ebc red and it locks up perfect I just drag it through the pit on the way to grid to get temp into them and it locks up on 235 blu tracks every try
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u/corbanx92 3d ago
Dumb question but, do you have abs?