Brake Master Cylinder and PDWA Questions

[jjbunn]

The TR6 brake master cylinder reservoir has two compartments. One at the rear, one at the front. Are these interconnected? How is one supposed to top up the front compartment: the opening is very small?

The front compartment on my leaking master was completely empty, and dry. It doesn't look as if there has been any fluid in there for a long time. Sure enough, when I removed the PDWA it also was dry as a bone on that circuit.

I thought I understood these systems, having worked on the MGB's! Another puzzlement: there is only one wire that attaches to the PDWA switch from the harness. I was expecting a pigtail, like in the MGB. I'm getting confused.

 

[DNK]

Basically it is already grounded and the rod is just connecting the circuit is how I always looked at it.

 

[TR3driver]

The TR6 brake master cylinder reservoir has two compartments. One at the rear, one at the front. Are these interconnected?

Should be a passage that allows fluid to flow to the front when the rear is full. As I recall, it's just a notch in the partition between the two sides.

The switch is supposed to ground the wire through the body of the PDWA; but might be defective. Obviously the body also has to be grounded for this to work.

 

[RobT]

The front reservoir on the M/C is for the rear brakes, and the rear (larger) is for thr front brakes. And you have to "over-fill" the larger brake reservoir to fill the other. I have found that after doing this you then have to bleed some of the fluid from the front brakes to reduce the level of the larger reservoir otherwise you can get fluid comming past the cap and possibly messing up the paintwork (unless you use silicone fluid which was my answer).

 

[jjbunn]

The front reservoir on the M/C is for the rear brakes, and the rear (larger) is for thr front brakes. And you have to "over-fill" the larger brake reservoir to fill the other. I have found that after doing this you then have to bleed some of the fluid from the front brakes to reduce the level of the larger reservoir otherwise you can get fluid comming past the cap and possibly messing up the paintwork (unless you use silicone fluid which was my answer).

Interesting: any idea why the front reservoir is not intended to be filled directly?

 

[DNK]

Interesting: any idea why the front reservoir is not intended to be filled directly?

It's British

 

[Brosky]

This will explain/show the PDWA switch internally and in detail.

https://www.britishcarforum.com/bcforum/u...9434#Post359434

 

[martx-5]

The front reservoir on the M/C is for the rear brakes, and the rear (larger) is for thr front brakes. And you have to "over-fill" the larger brake reservoir to fill the other. I have found that after doing this you then have to bleed some of the fluid from the front brakes to reduce the level of the larger reservoir otherwise you can get fluid comming past the cap and possibly messing up the paintwork (unless you use silicone fluid which was my answer).

Interesting: any idea why the front reservoir is not intended to be filled directly?

Isn't the real question 'where the heck did the fluid in the front reservoir go?'

 

[jjbunn]

Interesting: any idea why the front reservoir is not intended to be filled directly?

It's British

Hey! I'm British and my front reservoir gets filled directly!

 

[DNK]

Front or Back

 

[70herald]

Isn't the real question 'where the heck did the fluid in the front reservoir go?'

I have been wondering about that also. I hope that Julian is not driving around with front brakes only, but this really needs to be checked out.

 

[Bugeye58]

I don't think Julian has been driving at all, yet.
Jeff