B model hood latch repair

[Freightrain]

Well another 15 years and another latch gave up.  No spring pressure left.  New latches are square and $70 each.   Not what I want to spent or have.  After careful consideration I thought I could fix what I have.  Sure enough worked!

Cut the body apart with thin cutoff wheel at the bottom end.  Now they do unscrew but likely never get it apart.  I cut it about 1/2" from the end.  It came apart and showed how the spring was in pieces.  I then ground the head of the pin off so I could get the top off.  I then measured the pieces and found something close at the hardware store.  I then re assembled it and welded the cap on the pin and then welded the body together.  Some paint and you would never know it was apart.  I did constantly dunk it in cold water to keep the spring from loosing tension from heat soak(note I figured this out after ruining one spring).  Also make sure you assemble the lower portion of latch correctly or you might have to cut and weld it on correctly(ya I found that out the hard way).  In all it was easy and cheaper then new.  Looks correct too with the round style body.

 

welding the top back on the rod to hold spring:

 

Completed assembly

 

All the pieces cut apart, broken spring included:

 

This is just after I cut the latch apart:

 

This is the dimple you need to grind off to remove the cap on the end of the rod to get spring removed:

Edited June 6, 2016 by Freightrain

[j hancock]

Nicely done!  Got to love it when trucks can be repaired with hardware store parts.

[Freightrain]

the spring cost $1.46 and about 1 hour of my time.

[eddeere]

Nice job. Good information to have as I never know when mine will break.

[C609T]

Were exactly do you cut the body?  Do you have more pictures ?  Very good info so we can rebuild the old round latches instead of using the square ones which aren't original to B models

[Freightrain]

About 1/2+" up from where the pin comes out the bottom.  The threaded insert is about that long.  Gives you something good to weld into when re assembling it.  See 2nd picture from last.  They didn't upload in the order I put them.

The top picture you can see the lower mount is on backwards compared to the assembled picture below it.  I cut the mount and swapped it around once I realized it was backwards.

I edited the post to help tell what I did with each part.  I originally posted from my phone to allow me quick download of the pictures.  I added more text between the pictures to help make it easier to understand what I did.

Edited June 6, 2016 by Freightrain

[Mike]

Good job.....thanks for posting. I think I need to move to Canton, Ohio. Mack and Ford Country up there. 

[Freightrain]

Now that it has been a few weeks and I've used it, I can feel a slight difference in tension compared to an original.  I needed to find a STIFFER spring for the next ones.  Likely just a larger wire diameter.  I think I used a .047 wire.  I felt a .062 but it seemed too stiff.  I think it would be a tighter latch and likely use one on the next latch I rebuild.

Mike, only problem is we only have weather that is bearable for about 3 months a year....and it ain't around December!!!

[Wobblin-Goblin]

Interesting topic and thanks for sharing.

This past winter I had one hood latch that completely failed on my B81 project. After looking at it with my uncle and father, I decided to save time by simply buying four new DM style latches. Not knowing exactly what would be involved with repairing the innards, I figured if I replaced all of them with new, they'd be a matched set and be 100% ready to install (re: new and painted) when I got to that part of the project. Also, buying new would give me four original B model latches in reserve (three that were functional and one that I could repair in the future).

Now I know what to do with that one latch.

[Mike]

10 hours ago, Freightrain said:

Now that it has been a few weeks and I've used it, I can feel a slight difference in tension compared to an original.  I needed to find a STIFFER spring for the next ones.  Likely just a larger wire diameter.  I think I used a .047 wire.  I felt a .062 but it seemed too stiff.  I think it would be a tighter latch and likely use one on the next latch I rebuild.

Mike, only problem is we only have weather that is bearable for about 3 months a year....and it ain't around December!!!

Larry, we only get relief from cold about April then the smoldering humidity sticks around until October, November, then turns off extreme cold until April. So we only get about 3 decent months unless rain saturates the country side with floods. We have little bitty car get togethers in grocery store parking lots. Rarely see anything like a real ThunderBolt etc. etc. AC Cobra. I think maybe Jay Leno or some rich tycoon has all of them cars or the Schiek of the burning sands. Back in the mid eighties me and the former wife went to Milan, Michigan to watch the Drag Racing. I honestly have not had a good time since then. It was great weather and the people were not obnoxious like they are here.  

[Freightrain]

We have car cruises coming out the ying yang from May to Oct.  Any place you look, even during the week, has some kind of cruise in.  I haven't been to one in a very long time, just lost interest in sitting in a parking lot.  Heck I hardly even drive the hot rods anymore...........man does that make me old?  Or do I just feel old?  Ugh.

I was at Milan, Michigan last weekend for the Reunion race, our group runs in it.

[Timmyb]

Just an observation. The Spring is a coil, could it be screwed on past the pin head? It may make it easier to do next time with no need to cut or weld more than necessary. 

All in all you done a fine job of the repair  

 

Edited June 15, 2016 by Timmyb

[Freightrain]

I suppose you could screw it on?  But since you have to weld the body back together it is not that big of deal to put a dot on the top of the washer.  That is unless you can get the end of the tube to unscrew?

[Mike]

Sounds like both ways are a good idea. I could never figure out what strength the spring should be, usually too strong. 

[Freightrain]

I know one of the original ones is pretty tight.  This rebuilt version is a bit softer.  It holds the hood, but not as tight.

If you have good ones, I'd soak them in oil to keep the spring from rusting to pieces.  I know I did that years ago, but over time and lots of water it gets dry.  I tried to pack a bit of grease into it before I welded it together in hopes to keep it lubricated.

Edited June 16, 2016 by Freightrain

[Mike]

I would probably drill a small hole and thread it for a zerk or grease fitting. And just grease it now and then. There is a company called Lee Spring or leespring.com out of New York that has every kind of spring. I have their catalog and was in need of a new clutch spring, when I had the clutch and pressure plate rebuilt for the Mack. They had the exact spring I needed. They show the tensile strength and dimensions of any of their springs when you order from them.

[Freightrain]

My return spring was missing on my throw out arm when I pulled mine apart.  I did some measuring and came up with a spring at the local hardware just like the ones for the hood latches.  Maybe not the perfect one, but by golly it was better then the complete lack of one.  It was actually starting to wear on the TOB levers from the bearing just rattling on against the cast fingers for the last 50 yrs?  This is the one inside the bellhousing that pulls the bearing tight against the arm.

The latches actually do have a small oil hole in the top end.  I think that is where I squirted oil years ago since I didn't have to take them off to pour it with the latch upside down.  Though too much oil/grease and it will run down the fender when it gets hot outside.

[Mike]

Larry, i'm talking about using hard grease, not oil. Oil and grease won't hurt those ole Macks. That is why they are Bulldog Tough. 

[Mike]

Larry, i've been looking for Battlestar on You Tube when camera was inside and you were shifting. One of your early showings. I cannot find it. I thought it was really good.

[Vladislav]

Good job on that latch Larry.

I don't have any B's but will keep your experience in my mind. Might work out for something similar.