oldschool94

I have recently aquired a 94 accord ex and installed a new oem mc and it fixed the problem of now you have'm now you don't but they're still spongy. I beleive there's air between mc&abs. so do I bleed the mc through the wheels or the abs bleeder? and when bleeding the abs do you have a pumper like the wheels?

DCFIVER

No engrish????

MAD_MIKE

The ABS on the 94-97s has its own reservoir, and to bleed it you need to have a scanner capable of activating the pump to purge the system. You can pull the ABS relay and jump the terminals to activate the pump, but I am unsure of what the scanner does, does it just turn the power to the pump on constantly or does it pulse.*shrug*.

Just bled the brakes on the 95 EX. The fluid in the abs reservoir looked fine so I left it alone. I just bled the rest of the system with a vacuum pump like a non ABS car. FWD vehicles are diagonally split, usually you bleed them Driver Rear, Passenger Front, Passenger Rear, Driver Front.

As for the spongy pedal, prior to installing it, did you bench bleed the new MC? If not it can take much longer to bleed the MC in car as air bubbles can become trapped. If not fully bench bled the trapped bubbles will form an air pocket. Air is compressible, you will not be able to successfully bleed the system if you use the pumping method. And using a vacuum pump will still take quite a while to clear the bubbles all the way from the MC.

phootbag

Don't connect the bleeder to the washer nozzles.

Thumper74

'OMG, the brake fluid is blue!'

Mad Mike is right on the money! Did you bench bleed the master cylinder before install? If not, you may need to remove it and do so.

oldschool94

Thanks for your response's. Yes, I bench bled before install. I am going to try bleeding lines at mc itself,was reading another thread said it might work. here's the thing I don't understand how the system works.I know there's air in the line's but where? What is fluid travel? Is the mc transfering (sharing) fluid w/abs to the wheels (bleed whole system) or just bleed wheels.

DCFIVER

You did not bleed the MC once it was installed? Bench bleeding is not enough. You must also bleed the master once it is on the vehicle to expel the air from the open lines. Do not worry about the ABS. Bleed the MC at the first line,(furthest from firewall, then the 2nd line) You may also need to bleed the wheels, but not likely.

MAD_MIKE

If the system is opened, for any reason, you must bleed it.

DCFIVER

Not at all. If only the MC is removed, then only the MC and the lines at the MC need to be bled. Ive replaced hundreds, if not over a 1000 of them in the last 15 years, in fact I just did 2 yesterday, a 94 Civic and 91 Bonneville.

MAD_MIKE

How can you effectively bleed the lines, assuring there isn't any air in the connection? Unless there are some poppet valve type quick connections, I would not fully trust doing that. Either way, after replacing an MC would you not want to bleed the system to remove any possible contaminants from the system?

holmesnmanny

lol That doesn't make any sense. Where exactly does the air go when you just bleed the master cylinder and the area immediately around it ? Does it just disappear ? No it has to go somewhere and that is out of the bleeder valve at the wheels.

DCFIVER

Simply removing the lines from the MC is not enough to induce air through out the entire brake system. If there is any doubt ,it is easy enough to verify if there is any type of air in the system post repairs. However, pumping the brakes before bleeding the lines at the MC (like the OP did) may result in inducing air through out the brake system, but not always. In that case in may be necessary to bleed at the wheels after removing the MC. Other wise it is not necessary, if only for peace of mind for the inexperienced. As for contaminants, that would require a brake flush, which in a shop environment, is an additional labor charge. I make the recommendation based on the copper and moisture content of the fluid.
I understand your confusion, must seem like magic to you ,huh?

MAD_MIKE

I could see how you possibly could not induce a huge air bubble, but I still would not trust it.
Some vehicles just have soft brake pedals. Early 80s Mustangs come to mind. How can you be sure from just a pedal check?
Do you use those test strips that turn purple? If so how do you test the system if the MC was replaced? Do you test prior to removal of the old MC, or sample at the calipers? Are those test strips able to detect seal material? Or is there a more advanced/accurate way of testing the fluid?

holmesnmanny

No, it's not confusion, it's wrong. Bench bleeding(assuming that's what you're referring to) only helps speed up the actual on the car bleeding that you need to do when you replace the master cylinder.

Assuming you're referring to gravity bleeding the calipers, that will work but it will also allow moisture to get into the lines which is not good at all.

It is physically impossible to simply bench bleed the MC, then put it on the car and expect the system to be free of air. It's just not. Even if you do it as perfect as possible air is going to be in there. Bench bleeding only helps the rest of the bleeding it doesn't take the place of it.

holmesnmanny

To the OP, when you do your bleeding, make sure on the last pump,pump,pump,hold, that you crack open the bleeder valve and close it so fast on the last one that the pedal does NOT hit the floor. This will ensure that there is no chance of a tiny bit of air to reenter the system at the bleeder valve due to the pedal hitting the floor and a trace amount of fluid falling out before you close the valve. This is only necessary on the last pump,pump,pump,hold as each time you do it before that point any air will be pushed out after the next pump,pump,pump,hold.

Start with the furthest wheel from the master cylinder and work your way back to it closer so it should be pass rear, driver rear, pass front, driver front.

DCFIVER

Understandable, it comes with experience.
Right, but it does not matter how soft the pedal is, with out any assist(the car off) the pedal should become rock hard (after approx3 -4 pumps) and should not fade away. If you have even the slightest amount of air in the system the pedal will start to fade. That is how you check for air. It is fool proof. The brake system follows Pascals law and there are no "hidden areas" for air to hide, so long as no other components were removed. The air does not displace the brake fluid, it simply fills in the void left by the fluid you released during the repairs.
A simple check at the MC is all that is needed. Yes the test strips check for copper content, and brake fluid moisture tester (BFT) is used to check the H20 content. There is no purpose in checking for "seal" material. If the seals are deteriorating, they must be replaced. Seal deterioration is directly related to brake fluid condition.

DCFIVER

Confusion or reading comprehension fail. I cannot hold your hand, reread the thread....

DCFIVER

Wrong. The pedal hitting the floor will ensure that the calipers and or wheel cylinders are fully extended and will ensure that all possible air is removed.

Wrong. The system is split diagonal, that is not the order in which it should be bled.

holmesnmanny

That's correct, which brings us to this...

If the pedal hits the ground before you close that valve on the last pump,pump,pump,hold then there is a chance for a tiny bit of fluid to fall out past the valve, even tho the pedal reached the floor.

Looking over the alldata for a '93 prelude it does say rear pass, front driver, rear driver, front pass. But I have always followed the start with the furthest and work ur way back to the MC philosophy.

Be that as it may I haven't had any noise or squishyness in my brakes in ten years of diy'ing.

MAD_MIKE

MC in the '95 took a dump. Gotta love it when the rear seal blows. Postmortem dissection shows that there was a buildup of goo on the primary and secondary piston springs which caused corrosion. Rust occured, flakes fell off and took out the primary and rear seals. D'oH!
Internal bore has a couple of rust stains at the bottom of the bore where the secondary piston presses against the wall, and at the very rear where goo must have settled. Replaced the MC and re-bled with Castrol LMA.

I recall reading on here that one can actually bleed the ABS by cracking open the bleeder screw, which will depressurize via clearing the ABS of old fluid, refill the ABS reservoir and then cycle the key to re-pressurize. However, it did not re-pressurize. Cycled the key a few times and it still did not re-pressurize. Went for a drive and the reservoir in the ABS had dropped and the ABS did indeed pressurize. Is there a faster way, without scanners or having to go for a drive that the ABS system can re-pressurize or self bleed? I thought it would self check/pressurize itself if the key was cycled to ON(not start). Or does the engine need to be started for the pump to activate?

TIA

Lost Again

Engine has to start and run before the abs motor will "kick on".

DCFIVER

Neglecting the biennial brake flush,huh??
95 Accord ,yes? Crack the bleeder on the modulator and let the fluid flow into a container(via a hose) Close the bleeder. Start the car, allow the abs modulator to do its thing. Turn the car off and check the fluid. Repeat a couple of times until youre satisfied. (Note: a scanner is not utilized on this model year Accord, the procedure above is the only method I know of.)

MAD_MIKE

Thanks. I did try starting the engine but did not notice any sounds of the unit purging/pressurizing so I shut it off. When I went to bleed the '97 the unit seemed to kick on sooner, and that bleeding went very well.
Nope, well not since it's come under my stewardship. The car is not always in my possession and some 'maintenance' can be done. From what I understand the oil was checked and during this process it was noticed that the brake fluid 'needed to be topped off'(said person does not understand the correlation of the fluid dropping and pad wear). I'm guessing some form of cheap Dot 3 urine was used to fill the reservoir and in doing so reacted with either the LMA or directly attacked the coating on the piston springs creating the reaction with the springs.
This worked fine on the '97, the '95 seems to have a slower to react ABS unit. *shrug*