I can't find it! 1997 mint condition C1500 Chevy P/U. Only 65K miles. I first noticed that the brake pedal was going nearly to the floor, but would still stop fine. So I check and see the rear reservoir nearly empty. Refilled and brake pedal is now much firmer, but I cannot figure where the fluid escaped to. No drips visable anywhere. Ideas? Thanks.
Where is my brake fluid going?
- Thread starter gfh77665
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Out the back seal and into the brake booster most likely.
Yes, a rare leak into the vacuum booster is possible, but the most likely scenario is that the pads/shoes wore, the fluid level dropped too low, and you sucked a little air in the system.
Then, refilling allowed the master to self bleed and return to normal, or almost normal.
Then, refilling allowed the master to self bleed and return to normal, or almost normal.
As the brake pads wear, the pistons in the calipers moves outward to compensate for the wear. This requires more brake fluid to compensate for the larger volume in the caliper. Therefor, you must add brake fluid to the resevoir. This is the reason you should check it monthly. No signs of leaks, but brake fluid level will always require additional fluid as the pads wear.FWIW--Oldtommy
Originally Posted By: JRed
Or you have a seal in one of the drum brake pistons that's going bad. Those are hard to spot if its a slow leak.
+1! Exact thing happened on one of my rides years ago.
Or you have a seal in one of the drum brake pistons that's going bad. Those are hard to spot if its a slow leak.
+1! Exact thing happened on one of my rides years ago.
Any ideas why the front reservoir is not needing any refill? It's still topped off.
Agree with gfh post brake booster will hold fluid thus not showing the fluid leaking, as for the pads wearing true but you have plenty of fluid in the reservoir to allow for a NEW set of pads to be worn completely to the rivits and still have BF to spare also when you say the front and rear the front (smaller) is usually99% the rear breaks while the bigger or rear is the front. Can you pump up the brakes and hold them with the vehicle off this would be my first check if you suspect a leak.
Are the reservoirs front and back brakes or diagonal? I thought they were diagonal.
Could be a leaking wheel cylinder and most of the leaking fluid is inside the drum. First, pull the drums and check the cylinders. If they're fine, have someone pump the brakes while laying underneath the truck and inspect the lines for leaks. It may not drip at all unless someone is actually pressing on the brake pedal.
Originally Posted By: JRed
Or you have a seal in one of the drum brake pistons that's going bad. Those are hard to spot if its a slow leak.
I agree!
Or you have a seal in one of the drum brake pistons that's going bad. Those are hard to spot if its a slow leak.
I agree!
If only one side is leaking, you have just isolated 1/2 of the braking system as a potential problem [leaks downstream].
If it is the rear reservoir, it still may be the master leaking in the booster.
Why did you hide this information originally??
If it is the rear reservoir, it still may be the master leaking in the booster.
Why did you hide this information originally??
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Originally Posted By: mechtech2
If only one side is leaking, you have just isolated 1/2 of the braking system as a potential problem [leaks downstream].
If it is the rear reservoir, it still may be the master leaking in the booster.
Why did you hide this information originally??
Hide what information? I don't know what you are referring to. I said the rear reservoir was losing fluid in the first post. What are you talking about?
If only one side is leaking, you have just isolated 1/2 of the braking system as a potential problem [leaks downstream].
If it is the rear reservoir, it still may be the master leaking in the booster.
Why did you hide this information originally??
Hide what information? I don't know what you are referring to. I said the rear reservoir was losing fluid in the first post. What are you talking about?
Originally Posted By: Donald
Are the reservoirs front and back brakes or diagonal? I thought they were diagonal.
On that year of Chevy the larger rear partition in the reservoir serves the front brakes and the smaller front partition serves the rears. Diagonal systems are usually found on FWD, AWD & IRS vehicles.
If you can't find an external leak it is probably leaking out the back of the master cyl. into the booster as many have said above. Your booster will probably fail a year or so down the road if you don't replace it along with the master cyl., brake fluid is just about the only thing that ruins them. Just loosen the two nuts that mount the master to the booster a little bit and check for moisture, if you find any, that's your leak.
Are the reservoirs front and back brakes or diagonal? I thought they were diagonal.
On that year of Chevy the larger rear partition in the reservoir serves the front brakes and the smaller front partition serves the rears. Diagonal systems are usually found on FWD, AWD & IRS vehicles.
If you can't find an external leak it is probably leaking out the back of the master cyl. into the booster as many have said above. Your booster will probably fail a year or so down the road if you don't replace it along with the master cyl., brake fluid is just about the only thing that ruins them. Just loosen the two nuts that mount the master to the booster a little bit and check for moisture, if you find any, that's your leak.
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