1995 Plymouth Voyager HELP! BAFFLED (& FRUSTRATED) BY

BAHOP

MEMBER
1995 PLYMOUTH VOYAGER

Brakes problem
1995 Plymouth Voyager 6 cyl Front Wheel Drive Automatic 150k miles

basically I have had a SOFT pedal appear, disappear & reappear for over 9 mos. W/ NO visible discernible fluid loss

1 trip/1 day/1 week it's ALL firm & fine - the next trip /next day/ next week it's soft & the brake light comes on accompanied by a springy sounding click under the dash (which I assume is the pressure differential switch tripping?).

I have had 3 shops/mechanics assess it & heard 3 different opinions;

*shop#1 -says NO leaks -MC GOOD -booster BAD. Problem w/ that is I have vacuum pressure & NO hard pedal, also checked for fluid in booster & found NONE. Anyway -can a booster go out one day & not the next? So that doesn't seem to fit.

I have talked w/ several independent mechanics & spent considerable time online in forums & researching the problem. As in my previous post the consensus seemed to be MC so I replaced w/ a rebuilt one & all was FIRM & fine for about a week & then the next morning it's gone again.

**shop#2 bleeds complete system (but not sure
ABS mod was opened). They say left rear wheel cylinder is leaking & should be replaced. Aha! This makes sense & is my answer.

hire independent (flaky CL) mechanic to replace it & he adamantly says NO leaky wheel cylinder. I contest & question that & he says shop#2 trying to 'rip me off' (& why he no longer works for shops). He says rebuilt MC bad & should be replaced w/ new one - so I do.

brakes are FIRM & fine for another week & then gone again one morning. I bleed that circuit (suspected wh cylinder) & still seems to be air in the line. Once again all is FIRM & fine for a few days & then SOFT & brake light.

when it goes out, I can pump pedal a few times & light goes off & can get pressure back. Sometimes it stays awhile, sometimes it's gone by the next brake stroke.

more data (& questions);

---temperature & atmospheric weather changes seem to trigger the change. Can parts be expanding contracting w/ minimal seepage yet enuff to lower the hydraulic pressure?

--- my drive is a steep incline & I park w/ rear higher than front. Could trapped air be working thro the lines at these changes in angle?

I've sunk quite a bit of time & money into this @!#$% Problem already w/ NO resolution in site. I'm completely baffled & frustrated (& depressed) with it. I really don't know where to look next.

anyone HELP please? Would appreciate any theories -covered or not

thanx

bahop

4 Replies

BILLYMAC

MECHANIC
2,204 POSTS

Hi
Well one thing is certain there is air in the system.
And air not always easy to get out./ Some systems are more complicated then others.

You see if air was not the prob then bleeding any cylinder, would have made no difference.

However I would be very interested in the wheel cyl that was diagnosed by a shop. You didn.T say if this cyl was replaced this could cause air to enter system.

And the rubber seal you see on the end of the wheel cylinder is only a dust cover, there is a internal seal that commonly fails. While you can be ripped off by a shop none would be trying to rip you off for such an amount as a wheel cylinder.

But still we can't eliminate the wheel cylinder if you have not replaced it. And if it is the prob and does not get replaced the prob will never be repaired.

When I have a prob as do most technicians we eliminate probs by replaceing suspected parts, SUSPECTED this means we are unsure because it could fail in hard braking or even weather changes. So my advice change the wheel cyl both never wonder again if that is it.

Now BLEEDING fill master cyl crack all 4 bleeders put a rag or container under the drip go to bed next morn tighten all four fill master cyl pump up brakes no air guaranteed. Good luck let me know how this plays out interested

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Tuesday, September 21st, 2010 AT 8:48 PM

BAHOP

MEMBER
8 POSTS

OK I hear you. So far pedal holding (knock on wood) but it hasn't been a week yet & that has seemd to be the limit lately.

A bit more data. My front master cylinder cap is leaking- 1st I thot it was just spillage but it keeps coming back after wipe up. Could that compromise a sealed system? Not likely I'm thinking

but what about ABS? Could air get trapped in the modulator & then released when the system is used? I took to a 'brake chain shop ' to have the system BLED after replacing the MC the 1st time because the manual says my ABS needs a special tool to open the valve. I thought that's what they did but I found out afterward they didn't & I coulda saved myself 50 bux to do it myself. When I had/have soft pedal I'm able to pump it up for a stop or 2 & at times when doing this the left rear wheel (cylinder) in question has locked up & the only one to do so. ABS light never comes on & other wheels don't.

Any creedence to this theory? Or does it give rise to another? Or point even stronger to wheel cylinder?

Thanx

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Wednesday, September 22nd, 2010 AT 5:20 PM

BILLYMAC

MECHANIC
2,204 POSTS

Ok the leaking cap has to be repaired. It is not normal to cause air to enter system with just a leaky cap, however if the resavoir happens to run low on fluid, then yes this could happen.

Now getting back to that questionable wheel cylinder.
The wheel lock is a symptom of either misadjusted shoes or a bad wheel cyl.

ABS, You will find that all technicians will stray away from bleeding abs unless it has been opened for some reason.
They are two complete separate systems. The abs system is very complicated to bleed not like the hydro system.

This requires special tools and special training and most mechanics do not want to risk causing you more probs then you have.

Iwill just bet a service advisor told you, yes they will bleed the whole system. When the technician got the ro, I am sure he let the service writer know that he would not be bleeding the abs system.

The desk should have told you, but they didn, t. Typical

It is very important that your rear brakes are adjusted properly. If they are adjusted right, when you hit the brake it puts outward pressure on the shoes. If they are wrong you don, t have enough pedal travel to push shoe against drum and one or two pumps will push the wheel cyl shaft enough to give you a hard pedal.

If your ABS light works when you turn your key on and goes off when you start it. Then it is working ok.I still believe it is in the rear brakes mostlikely adjustment or wheel cyl. Lol that's my story and i'm sticking to it. Good luck

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Friday, September 24th, 2010 AT 6:18 PM

BILLYMAC