TheSamba.com :: View topic - Front reservoir not filling on brake master cylinder

Sun Sep 27, 2015 10:32 am

I have topped off the the brake reservoir however as you can see the front circuit is not filling. Is there any reason why the front would not fill with fluid? Should it have fluid?

Sun Sep 27, 2015 10:36 am

Longboardluv wrote: I have topped off the the brake reservoir however as you can see the front circuit is not filling. Is there any reason why the front would not fill with fluid? Should it have fluid?

Cant view the video, says it is "private" rather than a video, how about a description?

If you mean one side of the reservoir is filing and other not, could it be you have not filled the first side enough yet to overflow into the second side??? There is a dam between the two sides of the reservoir, one side must be filled almost to the top before the second side starts to fill as the fluid flows over the top of the dam.

Sun Sep 27, 2015 10:39 am

I changed it to public. Okay maybe I'll add more fluid.

Sun Sep 27, 2015 10:49 am

Longboardluv wrote: I changed it to public. Okay maybe I'll add more fluid.

Yeah just add a bit more, your probably really close to the top of the dam separating both sides right now per the photo.

The reason they put the dam in is to prevent both sides from running dry if say one of the side fails (say a rear wheel cylinder fails and leaks all fluid out, that would only drain one side of the reservoir.) BOTH rear wheels would now have no brakes as both rears are fed by one side of the reservoir, BUT both front brakes would still work as the dam prevented both sides from draining.

Good luck!!!! 8) 8) 8) 8)

Ps is this a kit car you doing??

I have a kit car and moved the reservoir to inside the cockpit on the front wall, just above and to the right of the pedals, feeding the master cylinder with the VW blue braided brake fluid hose. I hated filing the reservoir from under the car as yours is set up. also make sure that road spray cant get on the lid of the reservoir, as the lid IS VENTED on many reservoirs right into the fluid! The lid needs to be vented to allow for the displacement of fluid into the wheel cylinder's when brakes are applied and as pads wear. Some reservoirs have a rubber corrugated bellows under the cap that can expand as fluid is removed from the reservoir under normal use. the top of the diaphragm is vented so it can move, but this does seal off the fluid form the air, and water. If you keep the reservoir their, I would recommend obtaining one of the diaphragm caps.

Road spray thru the vent into the fluid is a serous problem. So consider ways to prevent it from happening. In that regard this location for the reservoir is less than ideal. A diaphragm cap is really necessary in this location

Many cars that have the reservoir in the front engine bay do use diaphragm caps because of road spray entering the engine bay in front engine cars. VW had not a problem with a no diaphragm as the trunk in the VW Bug is not susceptible to road spray,

Sun Sep 27, 2015 11:28 am

I believe that I have a diaphragm style lid see below...

Now my main problem is that the brake lights come on only after the pedal is about half way down. So under light braking they don't come on. But I tried hooking up the rear switch (see below) and it didn't work at all. Should I order a new one?

Sun Sep 27, 2015 2:51 pm

No, that is not a lid with a diaphragm, the diaphragm is huge, often it is a bellows. it will dip into the fluid. You have a plains old vented lid there. Water WILL get in thru this lid. It needs to be kept dry!!!!

for the brake lights, that can be a problem with pressure switches, with all the outfits making them, with no VW factory controlling the specification, you may have a switch that triggers at too high a pressure, either by design or defect. Try another.

I suppose you could try rapping it a bit with a small hammer to unstick something inside the switch but that is a long shot for a repair, you always want good working, fast acting, bright stop lights.

Sun Sep 27, 2015 3:25 pm

Okay I ordered too new switches!

Sun Sep 27, 2015 4:27 pm

Get a couple of piggy back clips and tie in the second switch

Sun Sep 27, 2015 4:43 pm

You only have one switch hooked up. Tie into both switches as Grandpa Pete says.

Sun Sep 27, 2015 4:55 pm

Where do you find the piggy back clips? I checked autozone and lowes. Maybe pep Boys? I'll definitely wire them up in series after I get the new switches!

Sun Sep 27, 2015 9:42 pm

Longboardluv wrote: I'll definitely wire them up in series after I get the new switches!

No! [-X You want to wire up the two switches in parallel, NOT series

Mon Sep 28, 2015 5:30 am

oh yes, sorry, miss typed that.

Mon Sep 28, 2015 3:18 pm

Could be not enough pressure on the working switch, front brakes might be at the end of cycle and rear switch is also not enough pressure. Make sure theyre bled real well.

Fri Oct 02, 2015 7:23 am

grandpa pete wrote: Get a couple of piggy back clips and tie in the second switch

it doesn't matter which wire goes to which side right? for example on the left switch, you could swap the wires and it would still work right?

Fri Oct 02, 2015 7:39 am

you can mix them up and it won't matter

I got the piggyback clips at Nappa

Fri Oct 02, 2015 7:41 am

okay another question.

I have my two brand new replacement switches. I've read that you swap them out without having to bleed the brakes. Does anyone have any experience swapping these out? I saw that if you are quick about it you can pull the old one and put in the new one pretty fast without introducing much air to the system.

Fri Oct 02, 2015 7:57 am

FIRST ...make shure the whole area is CLEAN .Push on the switches as you unscrew the last couple of threads to avoid leakage ; then as the switch comes out slide your finger over the hole while you start the new switch with the other hand . remember to push on the switch as you screw it in to avoid leakage .
DO NOT overtighten .. these aren't headbolts !!!

Fri Oct 02, 2015 11:17 am

grandpa pete wrote: FIRST ...make shure the whole area is CLEAN .Push on the switches as you unscrew the last couple of threads to avoid leakage ; then as the switch comes out slide your finger over the hole while you start the new switch with the other hand . remember to push on the switch as you screw it in to avoid leakage .
DO NOT overtighten .. these aren't headbolts !!!

two additional hints...
1.. fill the switch with brake fluid first, dip in clean jar of fluid and tap the switch to allow to fill (hole facing up) and air to come out, or use a clean eyedropper to fill the switch.

2.. put a saran wrap over the reservoir under the cap and secure cap so that the caps vent function no longer works, then the fluid will not drain out of the master when you remove the old switches.

Also, once it is running besure to take steps to keep road splash off the reservoir and cap as it is vented and water can enter thru the vent hole, or get a reservoir with a diaphragm to the fluid is not exposed to vented air. the location for the reservoir is not ideal from a water contamination stand point.

good luck

Fri Oct 02, 2015 11:37 am

bluebus and grandpa! THANKS! You guys are awesome!!!!

:) :D :D :D :D :D

Fri Oct 02, 2015 2:22 pm

For a vent you can put a small barb fitting in the cap & run a hose into the trunk area.