1970 Winnebago Brakes issue

[Doug]

Howdy. I am tasked with a "no Brake" issue on a 1970 Winnebago M-300. Chassis is a Dodge D24. The brakes are bled every year and they work for a short while. There is an issue with the. I am having trouble finding a manual for this to check out the brake system. Can anyone please help. Thanks, Doug

[Lakota Wolf]

Do you have fluid leakage at the wheel cylinders, along the frame or at The proportioning valve? Another issue can be the power booster, loosing vacumm.

[Doug]

Thanks to both of you Lakota Wolf and postman. I have not seen any fluid leakage and the reservoir is full. Where is the power booster located? I didn't see it near the master cylinder I think looking for a vacuum leak is a good idea.

[Lakota Wolf]

Power booster is usually mounted on the inside of the frame under the drivers area.(usually) about the size of a cantalope melon.. Another issue could be that while your rig is sitting, the seals in the master cylinder are seeping, Ive come across master cylinders that were only a couple years old failing due to bad seals inside them.  Hope this helps a little,, Diagnosis can be tricky at times.

[postman]

For the time being I am going to yield to Lakota Wolf and watch. Personally my first step is to check fluid level. Again personally, if fluid is low, time to put it on jack stands. But, I am not trying to get down the road...

[Lakota Wolf]

You have a valid point , I forgot to mention checking the brake fluid,. Thanks Postman.

[postman]

Lakota Wolf, Doug lends it to be assumed "bled every year" you would check. Not many people know that brake fluid can boil off, a different problem. 

[postman]

Dont consider this a diagnosis just information. Winnebago (dodge) used a bendix booster. A characteristic is that after pressed, the pedal will follow the foot back to its original postion. Reason so braking doesnt have to travel a full stroke to apply. If the pedal is slow to recover or not at all, the booster is suspect if Master cylinder is working.  Master Cylinder is first bled, then pressure tested. See LW on M.cyl. In that case the fluid squirts back into the reservoir indicated by pressure on the guage that immediately falls.

 

SERVICE DIAGNOSIS

Most brake problems are not caused by a power booster malfunction. The following brake problems are usually due to causes other than the brake booster:

• Grabbing Brakes
• Low Pedal
• Spongy Pedal
• Warning Light On
• Noise
• Pull to the Side
• Loss of Fluid

[postman]

please note heat shield

[Lakota Wolf]

Thanx for the info postman..

[Doug]

Thank you post man. I need to go look again, but I don't think the booster is attached to the master cyl. lilke that pic.

[Doug]

I think ours may be like this:

[Doug]

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