Will Not COAST

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
Post Reply
Brad Gates
G-First Lieutenant
G-First Lieutenant
Posts: 672
Joined: Sun Dec 22, 2002 8:47 pm
Location: Pennsylvania

Will Not COAST

Post by Brad Gates » Tue Sep 08, 2020 8:48 am

Situation Abnormal,
Jeep brakes seem to drag and Jeep will not coast on a slight grade. I have replaced: steel lines, brake wheel cylinders, master cylinder, shoes and resurfaced drums. BUT with all 4 wheels on the ground the jeep requires "extra" effort to push. Even on a slight grade it stays in position. I have tried backing off the brakes shoes so no drag, backing off the e-brake shoes, and even removed the rear d-shaft. With the jeep in the air on hoist all 4 wheels freely turn with one finger. On the floor is a different story. It feels that something? is dragging. SO I jack up rear axle with floor jack AND I can push the jeep with just a little effort, which seems normal. Rear brake drums and hubs do not have excess play, so I don't think the drums are binding with weight on jeep on the floor.
This was not checked before I replaced the above parts therefore I don't know if it was a pre-existing issue.
Any one run into this situation OR have any other thoughts/ideas?
Thanks,
BRAD


sjalbert
G-Colonel
G-Colonel
Posts: 1774
Joined: Mon Jul 30, 2007 11:28 pm
Location: Bellaire, TX

Re: Will Not COAST

Post by sjalbert » Tue Sep 08, 2020 9:58 am

Are the pads firmly attached to the shoes? Mine had a little slop in the rivets and would drag at pushing speed. The drag wasn't noticeable with the Jeep on a lift or when adjusting the shoes.
Seth
******
1944 MB 349858, 20620361
1942 MBT 10968 viewtopic.php?f=18&t=149552
1942 MBT 15799, USA 0217497 viewtopic.php?f=18&t=225199
MVPA # 8587
Com / Inst. SMEL
CFII - ASEL

Collecting Willys Engine Info. Please send me Engine #, Casting Date & Machining Date if known

mdainsd
G-Colonel
G-Colonel
Posts: 1370
Joined: Mon Oct 16, 2017 2:01 pm
Location: San Diego, CA

Re: Will Not COAST

Post by mdainsd » Tue Sep 08, 2020 10:57 am

Is it in four wheel drive?
52 M38 2X, '52 M37, '44 WC51, '42 WC 56/57, '50 CJ-V35(U), '42 GPW, '44 M3A1 Scout Car, 2010 M-Gator

User avatar
g.keating
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 282
Joined: Sat Mar 15, 2003 12:30 pm

Re: Will Not COAST

Post by g.keating » Tue Sep 08, 2020 12:58 pm

is your brake pedal adjusted properly

wc56daveyboy
G-Colonel
G-Colonel
Posts: 1773
Joined: Thu Mar 09, 2006 12:54 pm
Location: Colorado
Contact:

Re: Will Not COAST

Post by wc56daveyboy » Tue Sep 08, 2020 1:05 pm

As one other asked, is it in 4x4?

After installing my so called professionally rebuilt tranny and transfer, I’m getting binding in 4x4 LOW.

After removing transfer case pan, I can see why:

The sliding gear (item #42 I’m attached drawing)
Is somehow locked, or very tight.
Known as output clutch in some diagrams
In 4x4 mode the jeep
Is locked up. So I gotta take out my tranny/transfer and see what the H!!! is going on
Attachments
4E43D6E4-3A27-4828-A551-05CA2303F1C2.gif

Brad Gates
G-First Lieutenant
G-First Lieutenant
Posts: 672
Joined: Sun Dec 22, 2002 8:47 pm
Location: Pennsylvania

Re: Will Not COAST

Post by Brad Gates » Tue Sep 08, 2020 2:19 pm

Response to some of the questions;
BOTH drive shafts are off the jeep. So 4WD is not the issue.
Brake shoes are "backed-off" the drums with excessive clearance. So no chance of rubbing. Brake pedal has some free play before whl. cyl. are activated.
Will check tightness/rivets of friction material to metal base.
THANKS for the ideas.
BRAD

dpcd67
G-Lieutenant General
G-Lieutenant General
Posts: 7367
Joined: Mon Jul 25, 2011 4:41 pm
Location: Iowa

Re: Will Not COAST

Post by dpcd67 » Tue Sep 08, 2020 3:20 pm

Lift the jeep and try to turn each wheel by hand. It should be possible to do so. Then you will know which one it is.
U. S. Army 28 years.
Armor Branch

bazookajoe
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 249
Joined: Mon Feb 20, 2012 7:37 am

Re: Will Not COAST

Post by bazookajoe » Fri Sep 11, 2020 7:13 pm

Did you change out the hoses when you did the steel lines too?The rubber hoses have a tendency to plug up ,i have had the same issue. Brakes dragging and fluid not able to flow back,keeping the shoes engaged. I changed the hoses and cured the problem.

dpcd67
G-Lieutenant General
G-Lieutenant General
Posts: 7367
Joined: Mon Jul 25, 2011 4:41 pm
Location: Iowa

Re: Will Not COAST

Post by dpcd67 » Sat Sep 12, 2020 12:19 pm

Good point; when you replace brakes, replace everything; never do it one piece at a time. Steel and rubber, all wheel cylinders, and MC too. They are cheap.
U. S. Army 28 years.
Armor Branch

Brad Gates
G-First Lieutenant
G-First Lieutenant
Posts: 672
Joined: Sun Dec 22, 2002 8:47 pm
Location: Pennsylvania

Re: Will Not COAST

Post by Brad Gates » Tue Sep 15, 2020 7:07 am

Problem Solved,
After much time and trail and error, it was determined that with the weight of the jeep on the ground the right rear axle moved enough to bind the bottom of the brake drum on the bottom of the brake shoes. The problem was that the axle bearing race moved "in and out" of the axle housing. With the axle "out" the hub and drum would move "up" to contact the brake shoes just enough to create the drag. Apparently a previous repair used too many shims to adjust end play and the race was not forced into the axle housing properly. Sounds easy, but it sure took a lot of time to figure this one out.
Thanks for all the feed back.
Brad


Post Reply

Return to “M38 Technical Knowledge Base”

Who is online

Users browsing this forum: No registered users and 2 guests