Flex Brake Hose Failure

[Mike_B]

During my 4 year restoration of my 1953 M38A1 I bought a set of flex brake lines from one of the Jeep vendors (can't remember which one or when I got them), The lines have a silver fitting on both ends with ribbed black rubber lines. The crimp is a single barrel die that makes a 3/4" smooth crimp.

While driving out my driveway the other day I decided to test the brakes as I only put 28 miles on the Jeep so far. In doing so I heard a loud bang and my foot went to the floor. I limped it back into the shop and found the frame to front axle line had blown apart...the hose just got pushed right out of the crimp fitting.

I went on-line to buy a new line and in searching I learned my lines were NOT DOT certified. I found out that all companies making DOT Certified lines have their own unique number pressed into the fittings. I ordered a new set to replace ALL 4 flex lines...the new lines are braided stainless steel with a black PVC outer jacket...

So, if you have the type of lines described above you might want to look into replacing them...I'm just glad my line decided to come apart in my driveway and not on the road doing 50 mph.

Be safe!

Mike B
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Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer

[1948willyman]

That would not have been any fun.
Make sure your emergency brakes are working properly.
That is what they are there for and hopefully would help stop in a complete failure such as this.

[RonD2]

I've heard that using the "emergency" brake on the Willys jeep in a true emergency can be very dangerous.
That brake is on the drive line and if you lock up the drive line it can result in complete loss of control (along with everything else already happening very fast if your service brakes fail).

I always thought it was only supposed to be a parking brake, not an emergency brake. Don't know what the Army taught it's drivers about it.
Paragraphs 48 and 49 on pages 32-33 of the January 1956 edition of TM9-8012 don't say a word about using it to stop while moving.
Paragraph 20 on page 23 says it can be used in an emergency failure of the service brakes, but offers no advice on controlling the jeep if you do.

I'd recommend extreme caution before yanking that handle while in motion during an emergency.
I hope I never have to find out. Last resort better than dodging or nothing I suppose.

I just looked at my flex lines.
Double crimps on the fittings and the hose is marked with DOT numbers and the date made.

When it comes to brakes, I think buying top shelf and regular maintenance inspections is a good idea.

Good luck!
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Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

[wesk]

I have used the parking brake many times since i had my first jeep in 1971. It's not a big issue. The key to using it when moving is to never release your grip on the brake handle. It doesn't lock anything up and it doesn't toss you thru the windshield. I use to use the hand brake on my 54 M38A1 in SD when hunting in the black hills. We did a lot of hill climbing and the service brakes were quick to get hot and fade a lot. You just need to apply it gently and never allow the handle to get out of your hand so you can reduce and increase friction quickly under changing conditions. When use of the hand brake causing the uncomfortable jerking motions it is because you have neglected to keep the drum and pads clean.
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Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

[RonD2]

Yup. I get it for slow speed off-roading and hill climbing.

Try remembering all that during a panic stop with failed service brakes in traffic at 40 mph.
Good luck with that.

Like I said, it might be better than dodging (with one hand on the wheel and one on the brake handle) or doing nothing --- when it'll all be over in 3 seconds --- one way or another.

I think I'll buy quality parts, do regular maintenance, and take my chances.

To each his own....
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Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

[Mike_B]

I bought the lines from a well known military Jeep vendor a few years ago while I was in the chassis restoration phase of the project and I assumed they were DOT certified, I mean it's 2020, who would sell something not certified...my bad for not checking.

Also, just because the hose has DOT printed on it doesn't make it a DOT certified assembly

Anyway, I just mentioned this so someone else doesn't have a worse outcome than I had.

The hand Band Brake on my M38 is a lot more forgiving (it will slip before locking up)...the Dual Shoe on the M38A1 just grabs and locks up.

Confirm you have the good stuff with correct crimps and be safe!

Mike B
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Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer

[rgmutchler]

I don't know if this contributed to your brake hose issue but when I replaced mine during the rebuild process I noticed that at full front suspension relief the brake hose was stretched tight and preventing full suspension relief. I had purchased the hoses from a well known supplier and when I questioned him about it he told me not to worry about it.
My concern was that on rough surfaces the rubber brake line could break it the suspension went to full travel.
I went to the local parts store and bought some braked hoses that allowed for full suspension travel.
Ralph
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R G Mutchler
M274A5
M-38 MC13312
http://willysmjeeps.com/v2/modules.php?set_albumName=rgmutchler&op=modload&name=gallery&file=index&include=view_album.php

[Mike_B]

I did notice the new braided hoses for the axle to frame locations were about 2-3" longer than the ones I took off...

Mike B
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Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer