Hydrovac

Tracked, Halftrack, etc... Military Vehicles, Wanted, For Sale (NO AUCTION or EBAY), and Knowledge Base

Moderator: Kevin Lockwood

Post Reply
User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Hydrovac

Post by mkoloc » Wed Apr 10, 2019 6:28 pm

Pulled my master cylinder and hydrovac as I'm finally getting to the brakes on my track. Both items are French made Bendix items, no surprise there as this was a recovered French halftrack. Am wondering if anyone has had one of these hydrovac units on their track and if the can provide a model number of the hydrovac or a rebuild kit number. Both MC and Hydrovac had brake fluid in them when I pulled them today.

Image

Image

Image

Image
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Thu Apr 11, 2019 6:37 am

Bendix single piston hydrovac ..fairly common on trucks and bigger cars back in the day .. found a site that has a step by step procedure for teardown and rebuild of a similar hydrovac.. just need to get at it and then source the parts. PIA!! :?
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
1943Willysgpw
G-Major General
G-Major General
Posts: 2669
Joined: Wed Sep 11, 2013 10:02 am
Location: Edmond, OK

Re: Hydrovac

Post by 1943Willysgpw » Thu Apr 11, 2019 6:40 am

Looks the same as the G506 later versions. I have finally (I mean finally) found a unit for my GTB. It was the same as an first series version tandem piston. Yours looks to be the third single piston. Here is a chart.
Attachments
vacid.jpg
vacid.jpg (46.17 KiB) Viewed 272 times
"None of us are as smart as all of us"

1942 GPW 1871 DoD 2-27-42 Dallas Plant
1945 GPW 247890 DoD 1-26-45 Louisville Plant
1942 GTB 136166 DoD 9-18-42
1942 GTB 135938 DoD
1952 M100

User avatar
1943Willysgpw
G-Major General
G-Major General
Posts: 2669
Joined: Wed Sep 11, 2013 10:02 am
Location: Edmond, OK

Re: Hydrovac

Post by 1943Willysgpw » Thu Apr 11, 2019 6:45 am

Check this out. NOS rebuild kit. https://www.ebay.com/itm/Half-track-Whi ... ctupt=true OOPS. This rebuild kit is for an early version. I will leave it on here in case someone is looking for one. Try this instead. http://vehiclesofvictory.com/buying-sel ... -to-parts/ Scroll down the page and you will find this booster. (photo attached)
Attachments
chevy-hydrovac1.jpg
chevy-hydrovac1.jpg (44.75 KiB) Viewed 270 times
"None of us are as smart as all of us"

1942 GPW 1871 DoD 2-27-42 Dallas Plant
1945 GPW 247890 DoD 1-26-45 Louisville Plant
1942 GTB 136166 DoD 9-18-42
1942 GTB 135938 DoD
1952 M100

steve1973
G-Lieutenant Colonel
G-Lieutenant Colonel
Posts: 1170
Joined: Tue Mar 11, 2008 2:59 am

Re: Hydrovac

Post by steve1973 » Thu Apr 11, 2019 8:36 am

Check with Kevin Lockwood. He caries all the brake parts you need.

Steve A.
1941 White M2A1 (90% restored)
1945 M10 ammo trailer (restored)


User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Thu Apr 11, 2019 9:32 am

Thank you all .. definitely looks like the 3rd series to me. Was checking on Ebay thank you for that .. would love to have SN or model number .. will check with KL, thank you for that!!
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Thu Apr 11, 2019 9:46 am

Willys, my GPW has a build date of 7-21-42 out of the Dallas plant...small world :D

Mark

Image
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
1943Willysgpw
G-Major General
G-Major General
Posts: 2669
Joined: Wed Sep 11, 2013 10:02 am
Location: Edmond, OK

Re: Hydrovac

Post by 1943Willysgpw » Thu Apr 11, 2019 3:02 pm

Nice looking jeep.
"None of us are as smart as all of us"

1942 GPW 1871 DoD 2-27-42 Dallas Plant
1945 GPW 247890 DoD 1-26-45 Louisville Plant
1942 GTB 136166 DoD 9-18-42
1942 GTB 135938 DoD
1952 M100

User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Thu Apr 11, 2019 8:06 pm

Thank you, she is unrestored ...sitting in a hanger for 20 plus years when I got it.

The model number for that hydrovac is 374750 (3rd series) and was used by the Army in the 50's as a brake upgrade. My HT was a BM M16 to M16A2 Conversion for Korea in 1952, number 315 of 413 A2 conversions. So the Hydrovac change to 3rd series is now making sense.
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Sun Apr 14, 2019 6:17 pm

After doing a bit of reading and now having a clear understanding of the Hydrovac function I tore into mine this weekend. The outside was truly no indicator of my Hydrovac interior, which was increadible clean and beautifully preserved. Guess I shouldn't be surprised as everything else I'd opened up has been pristine. Those years of desert storage have been great for my preservation project. The third generation vac seems much simpler than gen 1 and 2 regards moving parts and design.

My leather diaphragm and the corded seal are still in excellent condition. The leather is supple and shows little to no wear. The cord seal is still white, pliable and in outstanding condition as is the blued retaining spring. Rubber cups and seals will need to be replaced, but the unit still had brake fluid in it when I pulled the brake lines and metal parts showed no corrosion. The biggest challenge was getting the big nuts loose on the valve body. The diaphragm body/shell is still shiny and there was a light layer of old dried lubricant on the leather boot. I plant to reuse both the leather diaphram and original rope seal, they are just to nice to toss out and replace ....

One interesting item I noted during my teardown, there was a cut washer hung up on the inside of the vacuum line where it bends coming into the vac. The check valve in the firewall is intact and the vacuum lines intact, so it's a strange bit of mystery that a cut washer made it's way down to the Hydrovac on the vacuum side. Maybe done by an errant mechanic back in the day?

Pics attached

Image

Image

Image

Image

Image

Image

Image

Image

Image
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Mon Apr 15, 2019 11:38 am

Just finished a very pleasant phone call with a gent at REMAN Inc, Atlanta GA. He is the resident expert regards all things Hydrovac and is sending a rebuild kit for my Hydrovac. He walked me thru the parts I need and clearly described each section of the hydrovac to include some tips on my assembly. Stated that he believes they may have some WWII hydrovacs still in cosmoline on the back room shelves. Sticking with what I have as it is original to my BM 1952 conversion.

$120 gets me all my parts for my rebuild 8) . Happy camper!!! Will post pics of the kit when it arrives.
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

User avatar
1943Willysgpw
G-Major General
G-Major General
Posts: 2669
Joined: Wed Sep 11, 2013 10:02 am
Location: Edmond, OK

Re: Hydrovac

Post by 1943Willysgpw » Mon Apr 15, 2019 12:55 pm

Looking good so far sir. How lucky for you that the insides were so pristine.
"None of us are as smart as all of us"

1942 GPW 1871 DoD 2-27-42 Dallas Plant
1945 GPW 247890 DoD 1-26-45 Louisville Plant
1942 GTB 136166 DoD 9-18-42
1942 GTB 135938 DoD
1952 M100

User avatar
mkoloc
LTC, U.S. Army
LTC, U.S. Army
Posts: 696
Joined: Tue May 29, 2007 10:52 pm
Location: 1631 Bitter Creek Lane, Batavia OH 45103
Contact:

Re: Hydrovac

Post by mkoloc » Mon Apr 15, 2019 3:10 pm

Very lucky and humbled by the excellent craftsman of the 40s and 50s.. Master cylinder was pretty crispy .. but much easier to replace than a hydrovac. :wink:
LTC Mark Koloc USA (RET)
MVPA Member # 31144
1631 Bitter Creek Lane
Batavia, OH 45103
Cell: 1.715.821.9426

Post Reply

Return to “Tracked”

Who is online

Users browsing this forum: No registered users and 5 guests