Disc brake valve rebuild with pictures

[terrible one]

Now that I'm addressing all of the issues with my Charger that I neglected due to "get it on the road fever," the next thing that came up is the proportioning valve. I did a disc brake swap years ago, not the average A body conversion, this was a hodge podge I think I ended up with 73 Charger spindles and E body calipers.

That said, I bought repro valve from Inline tube. When I went to bleed the brakes, I couldn't get any fluid to the rear wheels even after multiple attempts and troubleshooting. After a bit of resistance Inline had me send the valve back and they sent me another. This one did at least put fluid to the rears. When it was all said and done I had brakes but the brake warning lamp was on and they were less than desirable.

I have heard from other people about some of the Inline Tube reproduction brake blocks being machined in such a way that the brake warning lamp was always on.

Browsing Ebay the other day I came across an original disc brake valve and decided to give it a shot.

I also came across a fantastic resource, www.musclecarresearch.com. Not only is there an extensive article on disassembly/ inspection here: https://www.musclecarresearch.com/1970-76-mopar-combo-valve-autopsy but they have also made available a seal/ rebuild kit for both the Kelsey-Hayes and Weatherhead type valves for only $15: https://musclecarresearch.com/mopar-seal-kit-2

After reading the autopsy article I went ahead and purchased a kit from Scott for my Weatherhead type valve, and waited on it and the OEM valve to arrive.

Everything is covered in far more detail at Muscle Car Research, but I took a few pictures of the process with my own valve. It was actually in remarkably good shape, very clean and hardly any corrosion on the internal steel parts like the springs. Most seals were in good shape and still pliable, with one o-ring mishapen. The kit I received from Muscle Car Research was an exact match to the old seals, and I decided to replace them all.


Brake valve as received:




Plug, spring, and piston removed:




Next the switch for the warning lamp comes out so that pressure differential valve can be removed:




The bore was really clean inside!




Next the differential valve, spacer, and o-ring can come out:




Last was the only part that gave me a little trouble, the small piston located behind the valve. Muscle Car Research mentions that the piston can be hard to remove and that if tapping on the workbench doesn't get it, to apply air or hydraulic pressure. In the garage with no air, etc. I  couldn't get it out by tapping it. What I ended up doing was to put the plug back in place, and cover the rear brake outlet port tightly with my thumb. This left only 1 port behind the piston open, the one directly behind it which is the port from the rear brake reservoir at master cylinder. The size was perfect for the red straw on my can of brake cleaner. With the plug in place and my thumb over the other hole, I hit the brake cleaner. I could feel lots of pressure trying to push my thumb away and finally, after shaking the can of brake cleaner a bit, the piston shot into a cardboard box right next to me, actually went through it, which was nice because it kept it from shooting across the garage to who knows where.


Here it is, out!




After that, it was time to clean everything up. I used soap and water on the non-metal parts. The steel parts I simply hit with a wire brush and the brass I soaked in lemon juice (citric acid)




Make note of this piece, the spacer and o-ring.






Assembled and ready to go:





In hindsight, I should have had both the OEM and Inline valves apart at the same time to compare, but I try to have as little down time for the Charger as possible. Thus, I didn't take the Inline valve out until the OEM was ready to go.

Here's a couple of things of interest I found when I took the reproduction block from Inline Tube apart:

First, the switch. This valve has always had a small drip of fluid from this location. Also, remember how the brake warning lamp stayed on? If you look closely you will notice 2 things; the o-ring is badly crushed and mishapen due to the fact that there was almost no recess machined into this valve vs. the OEM one. No wonder it leaked! Also, hard to see, but there is what looks like a shiny spot on the screw head in the pictures, this is where it is making contact with the valve inside.




It doesn't really show in the picture , but looking inside, I can see where the screw head made contact with the differential valve. There was also a little brass shaving that had been created when the switch was tightened down and the two pieces made contact. You can see that, compared to the similar picture of the OEM valve during diasassembly, the piston is far enough to one side that the large diameter part is exposed, which is what is contacting the switch. I applied great force to this valve in the other direction and it would not move further into the valve. This appears to be the design flaw I had heard about; there is no way for the switch not to make contact with the differential valve, so the light will always be on.  




The other thing I noticed- remember the picture of the OEM piece that had the brass spacer and o-ring? The piece from Inline Tube has neither of those:




That's as far as I went with the Inline Tube valve autopsy. I couldn't get the small piston out with the trick I used for the OEM piston. Hell, seeing the differences in this one compared to the OEM there might not even be one in there!

Long story short, the OEM valve is in there and working perfectly, no warning lamp on, bone dry, etc.

I would HIGHLY recommend rebuilding your valve with the kit and AMAZING instructions from Muscle Car Research: https://www.musclecarresearch.com/1970-76-mopar-combo-valve-rebuild or buying a used one to rebuild. After buying an OEM valve and the rebuild kit I was still in it for less money than the reproduction block from Inline Tube, and I've got original parts that work!

Oh and if anyone for any reason wants the Inline Tube valve before I throw it away, you can have it for the cost of shipping.  

[Dino]

Great write up!   

So this valve is a combo valve and not a distribution valve?  Which model is this that it does not need the separate smaller valve?

[Nacho-RT74]

for those with laters dist blocks:
https://www.musclecarresearch.com/1979-gm-kh-combo-valve-autopsy

they sell the rebuild kits ( but the front section ). I got a couple of kits to rebuild couple I have laying around

[Dino]

I recently bought a used cast iron mopar valve, any rebuild kits available for those or are they the same as the GM valve?

[Nacho-RT74]

they are Kelsey Hayes... they made those for GM and Mopars... just changes the casting for the bolt on location, but inners are the same

[Dino]

they are Kelsey Hayes... they made those for GM and Mopars... just changes the casting for the bolt on location, but inners are the same

Great!  That means there will be parts for it until the end of time.   

[b5blue]

Real nice coverage of a needed service! 
Thanks!

[terrible one]

Great write up!   

So this valve is a combo valve and not a distribution valve?  Which model is this that it does not need the separate smaller valve?

Thanks!

Also, as far as I know, this is a distribution valve only, with the addition of the warning switch. I have seen the different combinations, I think that the smaller valve is a hold off valve that was used to engage the rear brakes slightly before the fronts to prevent nose dive. Take that with a grain of salt though!

When I bought my valve from Inline I explained to them my disc/ drum setup and they told me that they valve I have pictured is all I would need. Thus, that's all I got to replace it. As far as I can tell, braking performance is good and the fronts lock up before the rears, but I need to do some more road testing and make sure the rear drums are adjusted. I may find that I need a proportioning valve for the rear 

[terrible one]

Real nice coverage of a needed service!  
Thanks!

You're welcome and I appreciate it!!  

[fy469rtse]

Be wary guys, of that inline tube block , not saying its a bad one , but mine was ,
If you look at above photos , and look at a thread I started recently on mine ,
That bottom plug , bright finished,
The inline tube one made slightly different, the area that's recessed on the inline tube one is down past the threaded area, extremely thin, this plug seals with an o ring only , when they assembled mine , this was obviously tightened too much , it seeped when I bleed my brakes, I went to tighten it and it was finger tight, ? One of hose WTF moments,
It just kept turning, ? Huh, so I undid it, fluid everywhere, I glanced at the plug and it only had a couple of threads , the rest of the threaded area was still up in the block, it had sheared off at the bottom of thread and the depth of recess,
My advice , find an old one , and rebuild reseal it as above , not the only fault with it, shame on you inline for out sourcing this part to china,

[Dino]

Great write up!   

So this valve is a combo valve and not a distribution valve?  Which model is this that it does not need the separate smaller valve?

Thanks!

Also, as far as I know, this is a distribution valve only, with the addition of the warning switch. I have seen the different combinations, I think that the smaller valve is a hold off valve that was used to engage the rear brakes slightly before the fronts to prevent nose dive. Take that with a grain of salt though!

When I bought my valve from Inline I explained to them my disc/ drum setup and they told me that they valve I have pictured is all I would need. Thus, that's all I got to replace it. As far as I can tell, braking performance is good and the fronts lock up before the rears, but I need to do some more road testing and make sure the rear drums are adjusted. I may find that I need a proportioning valve for the rear 

That's what I thought as it looks just like my plain distributor block.  If you have drums in the back then you should have proportioning and metering valves.  If it turns out the brakes need more tweaking, I would look for the add-on valve, maybe a used on instead of the inline crap.  Those adjustable prop valves don't always work right and you'd still need a hold off valve and maybe a residual valve for the drums.

[Nacho-RT74]

they are Kelsey Hayes... they made those for GM and Mopars... just changes the casting for the bolt on location, but inners are the same

Great!  That means there will be parts for it until the end of time.   

actually the are not more than just O rings that once knowing the sizes you could get on specialized shops. Of course not made of regular rubber... is an special rubber ( the article says which kind of rubber is )

[terrible one]

Great write up!   

So this valve is a combo valve and not a distribution valve?  Which model is this that it does not need the separate smaller valve?

Thanks!

Also, as far as I know, this is a distribution valve only, with the addition of the warning switch. I have seen the different combinations, I think that the smaller valve is a hold off valve that was used to engage the rear brakes slightly before the fronts to prevent nose dive. Take that with a grain of salt though!

When I bought my valve from Inline I explained to them my disc/ drum setup and they told me that they valve I have pictured is all I would need. Thus, that's all I got to replace it. As far as I can tell, braking performance is good and the fronts lock up before the rears, but I need to do some more road testing and make sure the rear drums are adjusted. I may find that I need a proportioning valve for the rear 

That's what I thought as it looks just like my plain distributor block.  If you have drums in the back then you should have proportioning and metering valves.  If it turns out the brakes need more tweaking, I would look for the add-on valve, maybe a used on instead of the inline crap.  Those adjustable prop valves don't always work right and you'd still need a hold off valve and maybe a residual valve for the drums.

After a bit more research it turns out what I have is a proportioning valve and distribution block. What I took off of the car (4 wheel drum valve) was smaller and is the one that is a distribution block only. I did add in a 10 lb residual pressure valve to the rear brake line and it really helped with pedal feel (less travel). I feel like I'm good to go at this point, the car stops really well, I like the pedal feel, and the fronts lock up first. 

[terrible one]

Be wary guys, of that inline tube block , not saying its a bad one , but mine was ,
If you look at above photos , and look at a thread I started recently on mine ,
That bottom plug , bright finished,
The inline tube one made slightly different, the area that's recessed on the inline tube one is down past the threaded area, extremely thin, this plug seals with an o ring only , when they assembled mine , this was obviously tightened too much , it seeped when I bleed my brakes, I went to tighten it and it was finger tight, ? One of hose WTF moments,
It just kept turning, ? Huh, so I undid it, fluid everywhere, I glanced at the plug and it only had a couple of threads , the rest of the threaded area was still up in the block, it had sheared off at the bottom of thread and the depth of recess,
My advice , find an old one , and rebuild reseal it as above , not the only fault with it, shame on you inline for out sourcing this part to china,

Glad to hear that I'm not the only one with this experience.