metal brake / fuel pipes corrosion

[solarman216]

OK well got a working valve off, just need to be able to remove the hex bung in the end to dismantle it, job for the morning, but on first examination it seems that it monitors both front and rear pressures and via a spring loaded plunger adjusts the pressure to the rear brakes, the more it is pushed in the higher the pressure, if it is to be removed then it is vital that the front brake pipe is removed and blanked, Rick

 

[Mav96]

OK well got a working valve off, just need to be able to remove the hex bung in the end to dismantle it, job for the morning, but on first examination it seems that it monitors both front and rear pressures and via a spring loaded plunger adjusts the pressure to the rear brakes, the more it is pushed in the higher the pressure, if it is to be removed then it is vital that the front brake pipe is removed and blanked, Rick

Cheers Rick, when you say front pipe, is that the one running from the the 3 way splitter at the front in the above diagram ?

 

[solarman216]

yes there is a 4 way block at the front, master cyl,osf,nsf and the one to the rear which needs blanking if you do away with the load sensor, I have to go and do a small job now, will split the valve when I get back, Rick

 

[solarman216]

OK so successfully stripped the valve this is the body and internals in their corresponding positions

 

[solarman216]

Further disassembly, the bright cylinder is a shuttle and the other moving part is the right shaft, this has a one way valve in the left end which if it contacts the left shaft will open, it is not clear in the pic, I can see what is going on with this fella, but having done 3 drafts and re reading them I cannot get it right so at the mo given up, suffice to say the more the right shaft is moved to the left then the higher the pressure to the rear brakes, if anyone wants a full explanation then please say and I will endeavor to write something that can be understood, there are internal reliefs in the bright parts bore which only complicate a description, Rick

 

[Mav96]

Some more info learned, good job Rick.

 

[Lazy-Ferret]

The bit I do not understand Rick, is there is a lever with a Spring that connects to the Axel... Where does that fit into your pictures, and which bit does it move?

 

[rustic]

Some more info learned, good job Rick.

Fantastic, I knew roughly how it worked, but I didn't realise it had a link from the front brakes.

Amazing what you can do with mechanics and hydraulics.:thumb2

I am an electronics engineer (first career) and I understand electronic feedback, amplification, load sharing, resistance and voltage reduction, so the similarities are very similar.

A very clever design, amazing how rough it looks on the outside but pristine on the inside, I'm not sure anything electronic would continue to work for so long in that environment.
:clap:clap

 

[solarman216]

The bit I do not understand Rick, is there is a lever with a Spring that connects to the Axel... Where does that fit into your pictures, and which bit does it move?

the hook bottom right is the pivot for the lever and via an adjustable tit pushes against the right hand thinner shaft, the more load on the vehicle the more it pushes the shaft, there is also a spring between the lever and the body, on this one the bright shuttle was almost seized, and took some getting out, but once out realized it should have movement against the spring on the left as the larger piston cannot move due to always having positive pressure to the right of it, at first I could not figure out what the spring did but once realizing the bright part was a shuttle all became clear, Rick

 

[solarman216]

for further clarification the two left ports are feed from front brakes and bleed nipple, middle goes to rear drums, right is from master cylinder rear feed, Rick

 

[perelaar]

This had me confused (I am replacing my brake pipes at the moment). Setup on my is as described above by Rick. The Nissan repair manual image a bit higher in this topic has the line to the drums and the master brake cylinder rear feed switched?

 

[solarman216]

You are correct the drawing shows different set up, have to say the scrapper I removed the valve from had new pipes all round so possible they were wrong, will check other motors and see, Rick

 

[Mav96]

Ok so the first diagram I posted was without ABS
This one is with ABS but No LSV

[img=http://s20.postimg.org/7ztfd1hft/Brake_Lines_with_ABS_No_LSV.jpg]

 

[Smegg]

brakes

Hi i,m having the same problem [ that is my brother is i;m in no fit state at the mo to climb under it. Ihave had alook at the manual, briggies god send. My car has both abs and blv maybe change over model .i thinkthat causes confusion.in the manual one diagram shows without abs. But has blv one shows with abs no blv.check out the manual it does help. Not as much as the info you get on here from other members personal experiance,but its worth alook.if our kid finds any thing i can add i will.

 

[Mav96]

Also NOTE its the middle feed on the LSV which goes to the rear brakes, not as shown in the first diagram.

 

[Lazy-Ferret]

Hi i,m having the same problem [ that is my brother is i;m in no fit state at the mo to climb under it. Ihave had alook at the manual, briggies god send. My car has both abs and blv maybe change over model .i thinkthat causes confusion.in the manual one diagram shows without abs. But has blv one shows with abs no blv.check out the manual it does help. Not as much as the info you get on here from other members personal experiance,but its worth alook.if our kid finds any thing i can add i will.

My 99 T2 also has both Anti Lock Brakes, and the Load sensing Valve, not checked the wife's one yet.

 

[perelaar]

I have a 1997 SWB, 2.7TDI. No ABS, and brake line setup is, as said before, like Rick described.

 

[solarman216]

You are correct the drawing shows different set up, have to say the scrapper I removed the valve from had new pipes all round so possible they were wrong, will check other motors and see, Rick

All mine with the LSV have the middle connection to the rear brakes, never seen a LSV on a motor with ABS, and there seems to be different rear set ups with ABS my Mrs one for instance only has one pipe to the rear, so if ABS comes into play it can only operate on both rear wheels, very odd, Rick

 

[Blocky10]

All mine with the LSV have the middle connection to the rear brakes, never seen a LSV on a motor with ABS, and there seems to be different rear set ups with ABS my Mrs one for instance only has one pipe to the rear, so if ABS comes into play it can only operate on both rear wheels, very odd, Rick

That's how it is on mine. Rigid from each wheel to diff area, join with a t-piece and a short piece of flexi, connecting to rigid heading to the front.

 

[Mav96]

Ok been under Mav.
I have std 3 way connector on rear:
http://postimg.org/image/iqiw47qtl/