Create an account Home  ·  ·  Forums  ·  ·  Articles  ·  ·  Downloads  ·  ·  Photo Gallery  
Login
Nickname

Password

Don't have an account yet? You can create one here.

Navigation
· Home
· Article Archive
· Article Submit
· Downloads
· FAQ
· Forums
· Members List
· Photo Gallery
· Private Messages
· Web Links
· Your Account

Search Articles



Forums

Trade 3-52 M-100 for M-416
M38 Identification
Question on fuel tank filler tube
WTB: LATE M38A1 right front fender with vertical seam
The versatile M38
Windshield channel for canvas top
WTB M38 water pump housing
m38a1 meathook abortion
M38 replacement water pump
Wanted: M38A1 Late Battery Box Lid (Latch Type)

Willys M Jeeps Forums


willysmjeeps.com :: View topic - Brake Master Cyl/Lines advice needed
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Brake Master Cyl/Lines advice needed

 
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Technical Knowledge Base
View previous topic :: View next topic  
Author Message
longld
Member


Joined: Mar 21, 2017
Posts: 16
Location: Peoria, AZ

PostPosted: Sat Apr 15, 2017 12:59 pm    Post subject: Brake Master Cyl/Lines advice needed Reply with quote

Rebuilding my 53 M38A1 and brakes go to floor - Master Cylinder was empty of fluid - filled it and tried bleeding to one front and one rear wheel - no fluid or air. Pedal goes to floor easily and linkages look good. Suspect Master Cyl needs rebuilt and will do this next - when I remove this what is proper procedure to insure lines clear? Loosen all bleeder fittings and blow pressurized air or....? thanks!!!!
_________________
Lee Long
Peoria, AZ
1953 M38A1 USMC
Back to top
View user's profile Send private message Send e-mail
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 12889
Location: Wisconsin

PostPosted: Sat Apr 15, 2017 7:07 pm    Post subject: Reply with quote

Ex-military brake system usually left the military with DOT-5 silicone based brake fluid. The standard civilian fluids DOT-3 & DOT-4 are glycol based. The two are not compatible. The DOT-5 is the hardest to flush and remove all traces of. I won't get into the rediculous arguments between using DOT-5 and DOT-3 or -4. You can educate your self on what is the best choice to use from now on by just googling DOT-5 vs DOT-3/4. Suffice it to say I do not use DOT-5 and 99% of the automotive industry does not use DOT-5.

If you have no idea what your system has in it then just buy a can of DOT-3 and compare smells!

When dealing with an empty system you will normally have to fill the master cylinder several times. Now if you filled the master cylinder and pumped the brake pedal full stroke over twenty times and the master cylinder is still full then you have an issue with the master cylinder bypassing internally

In your case I would start by flushing the entire system with Iso-propyl-Alcohol. Strip clean with (Iso-propyl-Alcohol) & rebuild the master cylinder and all four wheel cylinders.

http://www.ucx.com/documents/brakefluidrev.pdf
_________________
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
Back to top
View user's profile Send private message Send e-mail Visit poster's website
skyjeep50
Member


Joined: Feb 20, 2007
Posts: 577
Location: Illinois

PostPosted: Sun Apr 16, 2017 8:54 am    Post subject: Reply with quote

If your brake master cylinder was dry you may want to carefully inspect all the lines and wheel cylinders for rust and gunk. If the vehicle had not been properly maintained the brake system may be gunked up to the point that a alcohol rinse will not really do much good. When I started working on my M38 the brakes worked but a look at what came out of the master cylinder and lines convinced me I would have to re-accommodate some parts.
Replacing the lines/hoses is pretty easy and will assure you that you can use any brake fluid you choose without contamination from what was used previously.
_________________
1 - 1953 M38A1
1 - 1951 M38
Back to top
View user's profile Send private message
whydahdvr
Member


Joined: Jul 18, 2008
Posts: 526
Location: Melrose, MA and Santa Fe, NM

PostPosted: Tue May 09, 2017 1:02 pm    Post subject: Reply with quote

Wes,
I'm looking up brake fluid information. It looks like:
A) I need to stick with DOT 5 fluid for my 1952 M38
Or
B) It doesn't matter what I use. ..

Your earlier post about not mixing the fluid types makes sense. I need to top off the fluids so which do I go with? I think it's the DOT 5 but want to confirm first.

Thanks!
_________________
North Shore, MA
Santa Fe, NM
1952 M38
1964 Apollo
Back to top
View user's profile Send private message Send e-mail
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 12889
Location: Wisconsin

PostPosted: Tue May 09, 2017 10:18 pm    Post subject: Reply with quote

The only way to confirm which fluid is in there is to smell it.

If you don't know what Dot 5 and Dot 3/4 smell like then buy a can of each sniff them and then sniff what's in your jeep.

Quote:
B) It doesn't matter what I use. ..


This is not an option. You can't mix them period.
_________________
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
Back to top
View user's profile Send private message Send e-mail Visit poster's website
whydahdvr
Member


Joined: Jul 18, 2008
Posts: 526
Location: Melrose, MA and Santa Fe, NM

PostPosted: Wed May 10, 2017 4:22 am    Post subject: Reply with quote

Thanks Wes.
We got it figured out. All set!
_________________
North Shore, MA
Santa Fe, NM
1952 M38
1964 Apollo
Back to top
View user's profile Send private message Send e-mail
Furley11
Member


Joined: Jul 24, 2016
Posts: 33
Location: Austin

PostPosted: Wed May 10, 2017 8:22 am    Post subject: Reply with quote

whydahdvr wrote:
Wes,
I'm looking up brake fluid information. It looks like:
A) I need to stick with DOT 5 fluid for my 1952 M38
Or
B) It doesn't matter what I use. ..

Your earlier post about not mixing the fluid types makes sense. I need to top off the fluids so which do I go with? I think it's the DOT 5 but want to confirm first.

Thanks!

I just did a full MC and line replacement in my M38. The cost and ease of doing it versus the problems that can arise (brakes going out) make it a no brainer to do a full replacement of MC and lines. Then, you can put whatever fluid you want to in there.
_________________
Furley
1951 M38
Amateur Tinkerer
http://www.willysmjeeps.com/v2/modules.php?set_albumName=album503&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Technical Knowledge Base All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB © 2001 phpBB Group
Forums ©

 



PHP-Nuke Copyright © 2005 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.