Brake Master Cylinder 94 Dodge Grand Caravan 3.3L

[William Pearson]

Pedal went soft and brakes barely stopping Caravan. Opened both caps of the brake reservoir and fluid was low on both sides. Would this indicate master cylinder failure? And where does the fluid go? Eric mentioned in his master cylinder video that the brake fluid can go into the brake booster. How do I check to see if there is fluid in the brake booster?

Topic

[Richard Kirshy]

Suggest you start simple..
Check your calipers, wheel cylinders and brake lines for any signs of leaks.
Then check the condition of your brake pads.
If that is all good.
You can pull the vacuum boost hose and see if there is any signs of brake fluid in it.
Past that you would need to remove the master cylinder from the booster and inspect both halves

[Larry Bible]

As the brakes wear, there is more volume in the caliper and wheel cylinders which takes some of the fluid from the reservoir. This is normal. That does not, however, mean that you don’t have a problem. A soft pedal almost certainly means air in the system or have a problem in the master cylinder, but could be at least partially due to really spoiled fluid. Loose wheel bearings can also contribute to the problem a bit.

Your best and most economic course of action, if you feel comfortable doing so, is to top off the reservoirs and bleed/flush the brakes. A quart of brake fluid would be enough to thoroughly flush the brakes. Not wasted effort/money even if you have to take it apart and loose the fluid. When you bleed after your repair(s) you will only have to add enough fluid to bleed and top off, saving the trouble of flushinig at that point.

If bleeding/flushing gives a hard pedal only temporarily, or just as likely doesn’t cure the problem and there are no leaks in the lines, at the wheels or around the ABS unit, then it is likely that you need to rebuild or replace the master cylinder.

Hope this helps

[Author]

Replies