Assistance with brakes needed

Military Trucks 2 1/2 ton and greater, Wanted, For Sale (NO AUCTION or EBAY), and Knowledge Base

Moderator: kw573

Post Reply
ragnar
G-Sergeant Major
G-Sergeant Major
Posts: 188
Joined: Mon Aug 24, 2009 5:24 pm
Location:

Assistance with brakes needed

Post by ragnar » Sun Jul 11, 2021 9:18 am

Fellow CCKW enthusiast. I am moving on with my restoration of my 1944 airborne transportable CCKW and have run into some major issues with the brakes. I replaced all of the brake lines with new steel lines that I bent and flared myself. I replaced all of the tee fittings and junction blocks with new old stock items. The flexible brake hoses are new made commercial parts. The rear wheel cylinders are New manufactured, US made, that I had sleeved with stainless steel. The front wheel cylinders are reconditioned with stainless steel lining. The type three Hydrovac is a replacement from Vehicles of Victory when owned by Tom Dienst. The fittings ,Bolt GM799389 and Connector GM2017610, for the Hydrovac are take off parts. I was not able to locate new parts for the Hydrovac fittings.

After completing all of the brake adjustments and adding brake fluid, I noticed leaking at all three of the brake Tees, GM2018842, and at the fitting connecting the Hydrovac to the brake lines, Bolt GM799389 and Connector GM2017610. There is another CCKW, early closed cab, under restoration at the shop where my truck is located and it appears to be leaking at the Tee fittings as well. One of the mechanics at the shop, a very experienced mechanic and all around smart guy, suspects that the modern washers may be made of a copper that is harder than it should be for a gasket washer. I am sure that over time this mechanic will figure the problem out and correct the issue. However, as a full time mechanic at this restoration shop, he has had to move on to other projects for the time being. I am sure he will eventually have the solution but I do not have the time to wait.

I have tried the usual fixes for these leaks such as tightening the bolts. I have incrementally cranked on the bolts in an attempt to stop the leaks without success. I am at the point that I am concerned that I will damage or brake the bolts at the Tee junctions. I am also concerned that the take off parts that I used for the hydrovac may have been used beyond their ability to be of use.

First off, I am wondering if anyone out there in G world has used one of the VOV replacement type three Hydrovac and if they ran into any similar leaking problems that they may have had to fix. Does anyone know of a source for the Hydrovac connectors, Banjo fittings, Connector GM2017610, and bolt Bolt GM799389? Does anyone out there know where better quality copper washers may be obtained? Has anyone had similar issue with their CCKW brake system? Any information or advise would be appreciated.


CTcckw
G-Private
G-Private
Posts: 4
Joined: Wed Apr 14, 2021 7:14 am
Location: CT, U.S.

Re: Assistance with brakes needed

Post by CTcckw » Sun Jul 11, 2021 12:11 pm

All the copper washer joints have a weep I take it? Take the washers back out :x and try annealing. Aka, heat over a propane torch then let them air cool, or even drop them in water. The copper will be renewed and super soft, so don’t over tighten. I can’t directly help with the other parts, but many banjo type bolts/washers are universal.

ragnar
G-Sergeant Major
G-Sergeant Major
Posts: 188
Joined: Mon Aug 24, 2009 5:24 pm
Location:

Re: Assistance with brakes needed

Post by ragnar » Sun Jul 11, 2021 1:08 pm

Thanks CTcckw
I will give the heating a shot. I have been told that the fitting are universal but so far the stuff I have found looks completely funky and nothing like what is on my CCKW. I am sure that you are correct regarding the parts being out there. The only question is where. Thanks again for the information. I suspect that I am not the only person that has experienced this issue and just need to connect with the other members that have already travelled this trail and can provide directions.

zoob
G-Sergeant Major
G-Sergeant Major
Posts: 186
Joined: Sun Jan 24, 2016 3:11 am
Location:

Re: Assistance with brakes needed

Post by zoob » Sun Jul 11, 2021 1:46 pm

Are you using Silicone brake fluid? Lots of guys have problems trying to stop this stuff from creeping/seeping.

ragnar
G-Sergeant Major
G-Sergeant Major
Posts: 188
Joined: Mon Aug 24, 2009 5:24 pm
Location:

Re: Assistance with brakes needed

Post by ragnar » Sun Jul 11, 2021 3:15 pm

DOT3. It is a weeping situation at the Tee fittings. It is a flat out drip at the hydrovac. I saw an old post on a CCKW forum regarding the OLD Vehicles of Victory replacement Hydrovac. The post only mentions that they were using a VOV type three replacement Hydrovac. I am hoping that these guys frequent this forum as well and can provide an update as to how it worked out. Still looking for solutions and parts source for the Banjo fitting and bolt that connects the Hydrovac to the brake lines.

Warren Duchesne
G-Colonel
G-Colonel
Posts: 1661
Joined: Sun Dec 22, 2002 6:47 pm
Location: Monroe , La

Re: Assistance with brakes needed

Post by Warren Duchesne » Sun Jul 11, 2021 5:28 pm

These banjo fittings have to be a lot tighter than you expect. Tighten them with good torque and recheck. Warren Duchesne

jesse
G-Lieutenant Colonel
G-Lieutenant Colonel
Posts: 1056
Joined: Fri Apr 07, 2006 6:26 am
Location: Albuquerque

Re: Assistance with brakes needed

Post by jesse » Sun Jul 11, 2021 6:14 pm

Brake lines must be double flared from annealed steel or they will leak. That includes stainless steel. The crush washers need to be copper annealed crush washers specifically for that purpose. Check used banjo fittings very carefully to make sure the sealing surfaces are intact. Brake Hoses Unlimited has crush washers and banjo fittings.

mudflap
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 313
Joined: Sat Dec 28, 2013 3:07 pm
Location: SE MI

Re: Assistance with brakes needed

Post by mudflap » Sun Jul 11, 2021 10:46 pm

Hi Ragnar,

I feel your pain. When I first got my truck, I went thru the entire brake system also - all new SS lines, new hoses, SS sleeves in all cylinders, new copper washers, the works.

I was still missing a new hydrovac, so I put a bypass line in its place, and pressurized the system from the master cylinder fitting using shop air. I sprayed soapy water on all of the fittings and was surprised to see bubbles at two of the tees (2018842) and also at the double flare connections to the valve that shuts off the front cylinders.

I had to replace the valve, as inspection showed that the contact area for the flare was pretty chewed up.

As for the tees, they were both OK at the flare connections, but were leaking at the banjo fitting bolt. I tried new washers, even annealed some, which helped, but there were still some bubbles presents. In looking at the tees, you could see that the sealing area (the concentric rings cast into the part) were not totally smooth. I ended up replacing them which fixed the issue.

When I finally got a replacement hydrovac unit (Type 3, Midland rebuild from NAPA) I installed it using the banjo fittings and bolts that came with the truck. I filled the system with fluid and bled it. The input was fine, but the output fitting had a very slight drippy leak. I took it apart, and noticed again, that the sealing surfaces of both the hyrdovac piston housing and the banjo fitting (cast concentric rings) had some minor imperfections in them. I annealed some copper washers and reinstalled the fitting. I partially tightened it, tapped on the bolt with a brass hammer, then tightened it again. That joint no longer leaks per see, but I do notice that it always seems to be "damp", as if there is just a small amount of seepage. Never enough to have to add brake fluid, never see drips, but frequently a very thin coating. Of course, the question is: Is this coming from the interface between the hydrovac and the washer, the washer and the fitting, or the fitting and the bolt?

A while back, I found a new bolt and banjo connector fitting on e-pay. The next time I need to service the hydraulic system, I am going to try replacing it. But if the issue is on the hydrovac side, I know its not going to help.

Some additional thoughts:

I agree with the theory that some of the copper sealing washer that are available today are harder than the originals, so I would anneal even new ones.

I have seen copper sealing washers with an integral o-ring. If the sealing surface has a lot of irregularities, this may be an option. This is an example: https://www.goodridge.co.uk/products/stat-o-seal-washer You just need to ensure compatibility with the fluid type and pressure level.

You could also consider a very, very, light coat of something like this on the surfaces prior to assembly:

https://www.henkel-adhesives.com/us/en/ ... e_567.html

You will need to clean the surfaces thoroughly first, and drain the system before assembly so the brake fluid does not wash it away as you are assembling the fitting.

Also, be careful not to tighten that bolt too much, as it is hollow and breaks easily.

WRT to replacement parts, you might try these guys: https://www.wildenbergparts.nl/
Not everything they have is listed on their site, so you probably will need to email them.

Best Regards.....

ragnar
G-Sergeant Major
G-Sergeant Major
Posts: 188
Joined: Mon Aug 24, 2009 5:24 pm
Location:

Re: Assistance with brakes needed

Post by ragnar » Mon Jul 12, 2021 7:09 am

Thanks Mudflap.
I have not tried Wildenberg for these parts. I get most of my parts out of Europe, mainly because of the lack of parts here in the states. The Wildenbergs know me well. I get a box of t shirts every now and then.

The Hydrovac connectors are the only parts that were not NOS, which may be the issue. The other suspected problem with the washer is possibly the thickness of the washers. I know that when checked with a micrometer, they were thicker than the ones that came out of an NOS brake kit. All of the other brake parts were new either NOS or new manufactured. I cleaned everything before installation. I wished I had used your compressed air method. The leaking brake fluid created a mess and gets expensive. I will try all that you suggested. I went to great lengths and spared no expense at obtaining the best parts I could find to avoid the problems that I am experiencing. I am quite perplexed and struggling to maintain my patience. Thanks again for the advice and suggestions.

Jhalye
G-Civilian
Posts: 1
Joined: Mon Oct 04, 2021 8:32 pm
Location: Schaefferstown Pa

Re: Assistance with brakes needed

Post by Jhalye » Mon Oct 11, 2021 8:03 pm

Have you made any headway?

ragnar
G-Sergeant Major
G-Sergeant Major
Posts: 188
Joined: Mon Aug 24, 2009 5:24 pm
Location:

Re: Assistance with brakes needed

Post by ragnar » Tue Oct 12, 2021 5:36 am

I have not had the chance to refill the system yet. I did, once again, replace all of the fitting with NOS fittings. I also replaced all of the copper washers with washers that I obtained from a company that supplies parts for the racing and aircraft industry. I immediately noticed that there was no more weeping from the wheel cylinders. I am a little leery of the washers that were put at the T fittings. These replacement washers were not as flat or wide as the original washers and seemed to shift as I tightened the bolts. I guess I will see after I refill the system with brake fluid. The lowest banjo bolt on the Hydrovac appears to have stopped leaking but may just be out of fluid. I will post an update when I take the next step.


Post Reply

Return to “Trucks 2 1/2 ton +”

Who is online

Users browsing this forum: No registered users and 5 guests