aint working. walk me through front brake system.

Started by DarkHelmet, November 18, 2023, 04:57:55 PM

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DarkHelmet

This is a brake system rebuild on an ongoing restoration.

I have the two-circuit system (yellow cap master) and the banjo bolt/pressure switch that fits into the banjo fitting. Previously I checked the rear drums and my vacuum bleeder sucked fluid through on both so the fluid has no problem going through the rear circuit.

But the front system. Now that I believe I have the proper-sided hoses (Goodrich) on the proper sides (yellow band on the RF I believe is it) I press the pedal, there's no buildup of firmess. There is no fluid going to the calipers. Ive even pulled the bleed valves completely out just to see fluid pump through and nothing. When I take the banjo bolt out, fluid then seeps all over so its coming out of the master into the banjo and where it's supposed to go there, which means it should go through the banjo bolt and down into the RF caliper, but it doesn't push through because I cant get any fluid out with my vacuum bleeder, each side.

So let's talk about the system itself and the fluid direction.
Out the master, to the banjo, where it comes into the banjo bolt, and out the back of the banjo simultaneously to both RF and LF calipers.So If it's going in fine, and the banjo bolt isn't clogged, then how can it get stopped entirely?

Im missing something.
1978 mini1000, A+ 998 engine.


DarkHelmet

1978 mini1000, A+ 998 engine.

94touring

Undo the lines into the calipers and check for rubber plugs?  If that isn't it, undo calipers and blow high pressure into the bleeder with it removed and see if it blows the pistons out.

MPlayle

Do you have the proper copper washers in the stack with the banjo bolt?  I seem to recall that there is one immediately under the head of the banjo bolt and another under the line fitting before it sits on the hose fitting in the subframe.  If these are not the correct ones (thickness), the holes in the banjo bolt become blocked by the edges of the fitting and no fluid will flow.

See these two diagrams from Mini Spares:

Brake diagram #1

Brake diagram #2

DarkHelmet

I have the proper washers, upper and lower. I'll undo everything again and check for deeper internal rubber things.
1978 mini1000, A+ 998 engine.