How To Rebuild a Heater Valve

[M3M3]

I have gone through a few heater valves. guts break, replace whole valve with another used valve, repeat. enough.

this time i bought a rebuild kit from BLUNTTECH. why buy a new valve when the brass part does not wear out, the kit includes EVERYTHING but the brass shell. rebuild is a VERY simple process.

 

so what do you need for this job?

 

• old valve
• rebuild kit
• flat blade screwdriver
• phillips head screw driver
• 7mm wrench
• small pick
• brass cleaner
• Dremel with wire wheel

 

NOTE - this is just the rebuild of the later "big" heater valves and does not include the removal or install of a valve.

 

The kit and the broken valve

remove two screw with flat blade, take cover off.

 

 

 

now use 7mm wrench to unbolt control arm from back

 

 

remove broken guts

 

 

old and new guts. new looks much stronger.

 

 

very important part here. main reason these valve fail (at least from all the ones i have taken apart) is that the inside of the valve corrodes in one spot becoming rough. Particularly true if the valve sits in one open or closed position for a long time. the plastic guts then hang up on the corroded area of the shell and break.

 

clean the inside of the brass shell until nice smooth and shiny. i used some 600grit and a dremel wire wheel to do this, then polished with metal polish like ibis or brasso.

 

 

now assemble the guts

 

 

don't forget the o-ring on shaft

 

 

i used a little teflon grease on all the parts.

 

 

assemble

 

 

 

now grab the cover. remove old o-ring with pick

 

 

same cleaning and polish rule applies to cover

 

 

install new o-ring

 

 

okay now put cover on the valve. note the position and alignment of the guts and the arrow on the cover.

 

 

use the new screws and lock rings to assemble (new parts are phillips heads)

 

 

put the control arm back on with 7mm wrench. don't forget the little washer.

 

note position of arm and open/closed valve. we are looking at the HEATER end of the valve in these picks.

 

 

 

 

DONE!

bagged up and ready for install at a later date.

 

 

 

 

 

 

 

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[gliding_serpent2]

Thanks for your latest two articles.  Although I am not in need of either at the moment, I appreciate the effort, attention to detail, and article/photo quality.  I am sure I will need these some day.  My only constructive criticism... too clean.  You make my car feel dirty.  Lay it off would ya?

[mrgesq]

Super helpful. This is on my winter project list.

[Sage]

Top notch! On my to do list.

[Dave G]

Great help! do you have a part number for the rebuild kit?  I've tried to look it up on BLUNTTECH and cant find it.

 

Thanks

[JohnS]

When I rebuilt my heater valves using this kit, I replaced the seals with different ones:

 

I ordered the new seals from: www.theoringstore.com

 

I ordered seals made of V75 Viton after reading about that material's properties on the store's website.

 

The small seal is 2mm x 8mm V75 Viton O-ring Black  Model: V2.00X008 -- (2mm thick, 8mm inner diameter)

 

The large seal is 1.5mm x 31mm V75 Viton O-ring Black Model: V1.50X31 -- (1.5mm thick, 31mm inner diameter)

 

I believe that the smaller seal in the Blunt kit is 1mm x 8mm -- (1mm thick, 8mm inner diameter, not sure of the material it's made of)

[02Les]

On 1/15/2015 at 9:45 PM, JohnS said:

When I rebuilt my heater valves using this kit, I replaced the seals with different ones:

 

I ordered the new seals from: www.theoringstore.com

 

I ordered seals made of V75 Viton after reading about that material's properties on the store's website.

 

The small seal is 2mm x 8mm V75 Viton O-ring Black  Model: V2.00X008 -- (2mm thick, 8mm inner diameter)

 

The large seal is 1.5mm x 31mm V75 Viton O-ring Black Model: V1.50X31 -- (1.5mm thick, 31mm inner diameter)

 

I believe that the smaller seal in the Blunt kit is 1mm x 8mm -- (1mm thick, 8mm inner diameter, not sure of the material it's made of)

 

John,

 

The small seal was originally a rectangular section seal, so, I'm curious how the "o'ring" one worked out. As it's been nearly 5 years since your message, if you've had no leaks then I guess it's good.

 

Cheers,

Les

[M3M3]

Well six years after install, the oring the blunt kit comes with is still working great! ?

[JohnS]

On 12/8/2019 at 2:04 PM, 02Les said:

 

John,

 

The small seal was originally a rectangular section seal, so, I'm curious how the "o'ring" one worked out. As it's been nearly 5 years since your message, if you've had no leaks then I guess it's good.

 

Cheers,

Les

 

Hi Les,

  I used the oversize 2mm x 8mm O-ring type seals on both of the valves I rebuilt for each of my cars using the Blunt kit and they are both still leak free.  Marshall is correct that many people have had no issues using the 1mm X 8mm O-ring seal that comes standard in the Blunt kit.  The 1mm x 8mm seal easily fits.  The 2mm X 8mm seals that I used have to sort of be "forced" into place.  The main reason I used the oversized seal was to give the O-ring more meat to act more like the rectangular section seal that was originally used.  After some time, the oversized 2mm seal gets reshaped and takes on a rectangular profile.  Good luck,

John

[02Les]

14 hours ago, JohnS said:

 

Hi Les,

  I used the oversize 2mm x 8mm O-ring type seals on both of the valves I rebuilt for each of my cars using the Blunt kit and they are both still leak free.  Marshall is correct that many people have had no issues using the 1mm X 8mm O-ring seal that comes standard in the Blunt kit.  The 1mm x 8mm seal easily fits.  The 2mm X 8mm seals that I used have to sort of be "forced" into place.  The main reason I used the oversized seal was to give the O-ring more meat to act more like the rectangular section seal that was originally used.  After some time, the oversized 2mm seal gets reshaped and takes on a rectangular profile.  Good luck,

John

 

John,

 

Thanks for the update. I've ordered the Blunt kit & the individual o'rings. I have several valves & a couple of them leak past the small o'ring as well as the one in the car.

Have to see if I can remove it without removing the Heater Box...….I really don't want to do that.

 

Les

[JohnS]

Les,

  Pulling and rebuilding the heater box is one of the 'rites of passage' in 2002 ownership ?  Seriously, it isn't as bad as people make it out to be.  It's a very satisfying fix once it's all back together and you've got a strong blowing HOT heater in the car.  I use my '74 as my surfing vehicle here in Northern Cali, so a good heater is a must for thawing out after a morning surf session.  That car gets exposed to all of the bad things (salt, sand, saltwater) and keeps on ticking. 

Good luck,

John 

[M3M3]

But it is completely unnecessary to mess with the heater box to replace the heater valve.

 

Unless you just like the extra pain and suffering....

[Mike A]

 some valves don't match the repair kit. The issue with the one from my 73 (not sure it's original) can be seen in the photos. The original diverter has no centering boss and  there was no centering centering hole in the cover plate. The new diverter sits proud of the valve body and has to be trimmed when using the original cover plate.

Edited December 14, 2019 by Mike A

[JohnS]

On 1/15/2015 at 7:45 PM, JohnS said:

When I rebuilt my heater valves using this kit, I replaced the seals with different ones:

 

I ordered the new seals from: www.theoringstore.com

 

I ordered seals made of V75 Viton after reading about that material's properties on the store's website.

 

The small seal is 2mm x 8mm V75 Viton O-ring Black  Model: V2.00X008 -- (2mm thick, 8mm inner diameter)

 

The large seal is 1.5mm x 31mm V75 Viton O-ring Black Model: V1.50X31 -- (1.5mm thick, 31mm inner diameter)

 

I believe that the smaller seal in the Blunt kit is 1mm x 8mm -- (1mm thick, 8mm inner diameter, not sure of the material it's made of)

 

Gentlemen,

  It's been brought to my attention by another FAQ member that my recommendation of using the Viton material for the heater valve O-rings might not be the best choice.  Perhaps the EDPM material would  be better?  

 

Sorry folks.  Just wanted to point out my error and open the subject up for debate.

 

Here's the descriptions from the O-ring store:

 

Viton:  avoid hot water, steam.  Yikes:  https://www.theoringstore.com/store/index.php?main_page=index&cPath=368_65

 

EDPM:  more better?  https://www.theoringstore.com/store/index.php?main_page=index&cPath=368_2278

 

Thanks,

John

  

[0257]

As the next step in my “climate control” refresh is to rehab the water valve, I am also very interested in the answer to this question.  Is Buna-nitrile a good long-term solution, or is EPDM better?  Having shopped for both, I know that certain sizes of EPDM are rarely stocked, at least by shops that’ll sell you just a few. Anyone out there with a 5-10 year experience with either?