1949 3800 chevt panel brakes

dougmayer · 08-19-2007, 01:49 PM

The brake pedal linkage is fairly tight. There is a little pedal play of less than 1 inch which I will look at. It may require a larger pin at the linkage of the brake arm to the master cylinder plunger rod. Other than that, I don't see any adjustment that can be made on the pedal assembly. The e-brake is out of the system until I can tie this problem down. All of the flexible lines to the wheel cylinder are new as well as the metal line that crosses the bottom of the engine. The lines that run between the front and back brakes along the fram member are original. Could these lines have gup in them. What would happen if I blue compressed air through the system?

crabtruck · 08-19-2007, 03:21 PM

You can post an "reply" to your own thread question so the whole conversation stays in one place.

If you blow air thru the lines you will have (duh) air in the lines, but worse moisture and probably oil as well. Very bad for brake system parts. Don't do it in my opinion.

You replaced the master many times ? You said if you pump it up and hold it, it stays pumped up. But when you let go and start over pedal goes towards floor. If you have checked for leaks, those two things say air in system to me. You said you bled the heck out of them, how did you do it ? How much new fluid did you push through system ?

pbouffard · 08-19-2007, 06:03 PM

id replace the lines between the front and back. and bleed the whole thing with a vacuum bleeder, question, did you bench bleed the master cylinder before you installed it, if not you wont get it bled correctly at all. you can remove the master and bleed it again if you dont know how ask you will receive by me or some other knowledgable person on this great forum.

dougmayer · 08-22-2007, 10:48 AM

This has been my first attempt on a truck forum after 32 years ownership of Big Blue, my 1949 1 ton panel truck. It took me 2-3 days to get the answer to my brake problem and 5 minutes to correct it. Thanks to Joe and Jerry, I adjusted the brake pedal at the clevis and master cylinder push rod which brought the pedal up to the level I remember when learning to drive the ’50 vintage pick ups back in the late 1950’s. I discovered that the check nut was loose adding to the dilemma that took 32 years and 5 mechanics to resolve (some of which said that there was no adjustment).

Hooray for the forums.

Now then, here’s another 32 year problem I’ve had with engine mounts on my truck which was solved several months ago and would like to pass on to you. When I bought the truck, I replace the nearly shot 216 engine with a brand new never uncrated 1955 235 engine. Over the next 32 years, I would go through rear engine mounts that would eventually tear apart. The engine being unstable would cause the clutch to chatter. I suggested to my parts suppliers that maybe the torque produced by the larger engine and the resistance of the heavier 1 ton truck (vs a ½ ton) was to great for these engine mounts. I solved the problem by finding a totally different designed motor mount that bolts up to my engine. It’s GM group no. 0.029 part no. 3711027.

08-19-2007, 01:49 PM	#1
dougmayer Junior Member Join Date: Aug 2007 Location: Dawson County N. Ga Posts: 9	1949 3800 chevt panel brakes The brake pedal linkage is fairly tight. There is a little pedal play of less than 1 inch which I will look at. It may require a larger pin at the linkage of the brake arm to the master cylinder plunger rod. Other than that, I don't see any adjustment that can be made on the pedal assembly. The e-brake is out of the system until I can tie this problem down. All of the flexible lines to the wheel cylinder are new as well as the metal line that crosses the bottom of the engine. The lines that run between the front and back brakes along the fram member are original. Could these lines have gup in them. What would happen if I blue compressed air through the system?

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08-19-2007, 03:21 PM	#2
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,107	You can post an "reply" to your own thread question so the whole conversation stays in one place. If you blow air thru the lines you will have (duh) air in the lines, but worse moisture and probably oil as well. Very bad for brake system parts. Don't do it in my opinion. You replaced the master many times ? You said if you pump it up and hold it, it stays pumped up. But when you let go and start over pedal goes towards floor. If you have checked for leaks, those two things say air in system to me. You said you bled the heck out of them, how did you do it ? How much new fluid did you push through system ?

08-19-2007, 06:03 PM	#3
pbouffard Senior Member Join Date: Apr 2007 Posts: 100	id replace the lines between the front and back. and bleed the whole thing with a vacuum bleeder, question, did you bench bleed the master cylinder before you installed it, if not you wont get it bled correctly at all. you can remove the master and bleed it again if you dont know how ask you will receive by me or some other knowledgable person on this great forum.

08-22-2007, 10:48 AM	#4
dougmayer Junior Member Join Date: Aug 2007 Location: Dawson County N. Ga Posts: 9	This has been my first attempt on a truck forum after 32 years ownership of Big Blue, my 1949 1 ton panel truck. It took me 2-3 days to get the answer to my brake problem and 5 minutes to correct it. Thanks to Joe and Jerry, I adjusted the brake pedal at the clevis and master cylinder push rod which brought the pedal up to the level I remember when learning to drive the ’50 vintage pick ups back in the late 1950’s. I discovered that the check nut was loose adding to the dilemma that took 32 years and 5 mechanics to resolve (some of which said that there was no adjustment). Hooray for the forums. Now then, here’s another 32 year problem I’ve had with engine mounts on my truck which was solved several months ago and would like to pass on to you. When I bought the truck, I replace the nearly shot 216 engine with a brand new never uncrated 1955 235 engine. Over the next 32 years, I would go through rear engine mounts that would eventually tear apart. The engine being unstable would cause the clutch to chatter. I suggested to my parts suppliers that maybe the torque produced by the larger engine and the resistance of the heavier 1 ton truck (vs a ½ ton) was to great for these engine mounts. I solved the problem by finding a totally different designed motor mount that bolts up to my engine. It’s GM group no. 0.029 part no. 3711027.