Brake / soft pedal trouble shooting, Brake pedal gone soft and fluid reservoir empty Options

[Fart/4]

Had the car for about 15 years
Never touched the brakes as in original ( to me )
Rotors , pads etc

Over the last about 100 miles brake pedal has gotten progressively
Softer and now go's down to the floor pretty much

Checked the reservoir and it's bone dry

Car still stops reasonable we'll , but pedal is very soft and is about 80% travel when brakes bite or engage

Should i immediately just take it to my aircooled guy/ mechanic

Or refill the fluid and see what happens approach
?


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[emerygt350]

Ouch, yes take it to your guy.

Asap.

[emerygt350]

A refill before you leave is well advised. Whatever you put in will join whatever you lost but it will help you stop in the meantime.

And in the future remember you should have your fluid flushed every few years as it picks up water.

[Superhawk996]

Check floor pan inside car at the pedal cluster and/or under the carpet.

You will most likely find your lost fluid there due to bad master cylinder.

If that is where your fluid is; should have the vehicle flatbedded to repair rather than risk loss of brakes during the drive.

[sixnotfour]

no brake light on in dash ? does it flash when handbrake is on ?
safety circuit something check out too..

[fiacra]

You're lucky that you haven't had full brake failure yet. Whenever there is a change in how your brake pedal feels that should trigger a full inspection. Playing the odds, the MC is leaking into the car. Pull the pedal board and you'll likely find all of your missing brake fluid at the base of the pedal cluster. Depending upon how much exposure to brake fluid it has had, you may need to rebuild your pedal cluster. At a minimum you need to thoroughly clean that up as brake fluid is damaging to paint as well as to the bushings on your pedal cluster. Soap and water will do.

Should you top off the reservoir and drive it to your mechanic? I would say no, but that's up to you. If you have AAA, have them tow it there. If the reservoir has gone fully dry, then you have air in the system, and you won't have a strong pedal. Even if you don't, why risk catastrophic brake failure by driving with a failed master cylinder? If not for you own sake (and the sake of your car), but also think about how you are putting other people at risk. Just have it towed in.... To me that is a "no brainer"

[930cabman]

Check floor pan inside car at the pedal cluster and/or under the carpet.

You will most likely find your lost fluid there due to bad master cylinder.

If that is where your fluid is; should have the vehicle flatbedded to repair rather than risk loss of brakes during the drive.

+1, you will not find any fluid on the ground, all the leaking fluid will be under the pedal cluster, and yes - flatbed is the safe call

[mepstein]

I once had my brake pedal go to the floor just as I pulled into my garage. I pulled the handbrake just in time to keep the car from hitting the wall. New master cylinder went in the next day. Don’t ever drive with compromised brakes. It’s definitely not worth the risk.

[bkrantz]

PLEASE don't drive the car until fixed.

And in the future when you notice brake problems, check the reservoir sooner.

We don't want to lose you or your car.

[76-914]

Check floor pan inside car at the pedal cluster and/or under the carpet.

You will most likely find your lost fluid there due to bad master cylinder.

If that is where your fluid is; should have the vehicle flatbedded to repair rather than risk loss of brakes during the drive.

+1, you will not find any fluid on the ground, all the leaking fluid will be under the pedal cluster, and yes - flatbed is the safe call

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[GregAmy]

Had the car for about 15 years. Never touched the brakes as in original (to me) Rotors , pads etc

Might I suggest a refill and bleed? Or even better, new brake pads, then refill and bleed?

And are there any obvious leaks?

Reason I offer this, if you are still on your original brake pads, and there's no leaks, you may have simply run the brake fluid level too low due to normal wear of the pads. As pads wear, the pistons extend farther out and that lowers the reservoir fluid level. If you allow your pads to wear too much without regularly replenishing the fluid, you may have simply run it too low and started sucking in air*.

If this is the case, then a refill and bleed will resolve your brake pedal. However, this implies your pads are significantly worn out. Note that if you replace the pads after fill/bleed then you will overflow the reservoir as you are pushing back the pistons for the pads replacement...that's why I say replace pads first, refill the reservoir second, then bleed/flush the fluid last.

And if none of this mean anything to you then yeah, bring it to your guy to check out.

GA

*I don't have a hard date, but I think it it wasn't until sometime in the early- to mid-70s when the Federal Motor Vehicle Safety Standards (FMVSS) started requiring brake reservoirs large enough such that completely-worn-out pads/shoes all around would not result in air being introduced into the system.

And that does not take into consideration any leakage, introduction or water/contaminants, and/or evaporation.

S5.4.2 Reservoir capacity. Reservoirs, whether for master cylinders or other type systems, shall have a total minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position (as adjusted initially to the manufacturer's recommended setting) to a fully worn, fully applied position, as determined in accordance with S7.18 of this standard.

[fiacra]

Had the car for about 15 years. Never touched the brakes as in original (to me) Rotors , pads etc

Might I suggest a refill and bleed? Or even better, new brake pads, then refill and bleed?

And are there any obvious leaks?

Reason I offer this, if you are still on your original brake pads, and there's no leaks, you may have simply run the brake fluid level too low due to normal wear of the pads. As pads wear, the pistons extend farther out and that lowers the reservoir fluid level. If you allow your pads to wear too much without regularly replenishing the fluid, you may have simply run it too low and started sucking in air*.

If this is the case, then a refill and bleed will resolve your brake pedal. However, this implies your pads are significantly worn out. Note that if you replace the pads after fill/bleed then you will overflow the reservoir as you are pushing back the pistons for the pads replacement...that's why I say replace pads first, refill the reservoir second, then bleed/flush the fluid last.

And if none of this mean anything to you then yeah, bring it to your guy to check out.

GA

*I don't have a hard date, but I think it it wasn't until sometime in the early- to mid-70s when the Federal Motor Vehicle Safety Standards (FMVSS) started requiring brake reservoirs large enough such that completely-worn-out pads/shoes all around would not result in air being introduced into the system.

And that does not take into consideration any leakage, introduction or water/contaminants, and/or evaporation.

S5.4.2 Reservoir capacity. Reservoirs, whether for master cylinders or other type systems, shall have a total minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position (as adjusted initially to the manufacturer's recommended setting) to a fully worn, fully applied position, as determined in accordance with S7.18 of this standard.

Not bad advice IF your pedal is slowly going lower over a long period of time. However in this case the pedal got softer and lower over the period of time it took to drive 100 miles. Can't see pad wear as the culprit here. I'm going to take MC failure with leaking at the pedal cluster for $100 (IMG:style_emoticons/default/biggrin.gif)

[GregAmy]

Not bad advice IF your pedal is slowly going lower over a long period of time. However in this case the pedal got softer and lower over the period of time it took to drive 100 miles.

Though I am not discounting a potential master cylinder failure, all it takes is one burp of air sucked into the MC from an empty reservoir to cause an immediate, continuing, and dramatic loss of hydraulic pressure...you know, like when air is introduced into the system by a master cylinder failure.

Supporting that is the lack of notation of a visible leak, plus the "15 years" comment (how many miles/hours?) implying that regular inspection of the brake fluid level may not have occurred.

But yes, by all means, get it checked out. - GA

*"Ask me how I know"? Answer: from decades of bleeding race car brakes and being stoopit and not monitoring the reservoir level...one miscalc and the reservoir drops too low and then the pedal goes directly to the floor and you get to start aaaalllll over again...

[Fart/4]

Appreciate the info

I removed the carpeting around the pedals and
See no sign of leak
So

I put half a small bottle of brake fluid into the resivoiur
And several bubbles immediately came up
And after a 3 mile drive the pedal is now very firm and the breaks engage and bite
Right at the top of pedal travel

I will continue to monitor the level
And take it to the mechanic for brake hose
Inspection as I suspect that to be the culprit
Follow-up by pad and disc inspection and master

I currently have a 93 7.3 idi cab chassis econoline
Getting it's trans rebuilt and until I get that back
I'm gonna put off the 914 brake inspection
As I don't like having more then 1 vehicle in the shop ( shout out to the cheap sob ) (IMG:style_emoticons/default/first.gif)


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