90 Eldroado brake problem

[What job]

Hey all,

Well the Father in-law has returned from the mainland . And the complaints about his 90 Eldo pulling to the right when the brakes are applied have started again . As well , he has now been complaining about poor fuel mileage . Well ... today for reasons I won't go into , I had to drive his car .

First thing I noticed was the hard pull to the right , just as he said . Next was the obvious feeling that the front brakes weren't releasing .

At least it sure feels as if the front brakes are not releasing . This of course would explain the poor fuel mileage .

This car only has 80k on it , and of course spends most of the time parked . One of the front calipers was replaced a couple of years ago at a local shop , which seemed to help the pulling to the right . I suspect that maybe when the caliper was replaced the addition of fresh brake fluid into the system may have helped a sticking proportioning valve , and this was the cause for the improved braking . The shop said that after replacing the caliper it found that the caliper was not the cause of the braking problem , but they had found a kinked brake line that they felt was the problem . How they missed a kinked line before the caliper replacement is not known . But seeing as to how the same problem has returned , I have to think there's another cause other than a kinked line , or sticking calipers .

Any thoughts on whether or not the proportioning valve could cause the sticking front brakes ? Any thoughts of why the front brakes are not releasing ?

Thanks for any input , and I hope all have a happy holiday !

[dmk9561]

Make sure that the rubber brake line going to the RF caliper isn't old. If it wasn't replaced, I'd go ahead and try replacing it first. Old rubber brake hoses can form a remarkably good check valve inside that can keep the brakes from releasing properly. It's happened to more than one car in our family to a hose that looks ok from the outside, but it's usually the OEM hose on a car that's over 10.

[What job]

Thanks davek ,

I believe that's the side the caliper was replaced on , so it would make sense that the line going to it might have an issue . More so if the line had been twisted in some way at one time .

The problem I see with it being a bad line is both front brakes seem to be sticking .

When I backed out of a parking spot the car came to a stop on it's own . Just like the brakes were applied . When it was then driven forward , the front wheels felt as if they were dragging equally . After being in stop and go traffic for awhile the car developed a shaking in the front end . A shake like the one felt when applying hot brakes. However , the shaking does go away after a few miles of continued non stop driving . It feels like I'm power braking when trying to start from a stop . The brakes do release to a drivable point , but it seems that they never totally release . I'll have a look see at the hoses . It'd be very unusual for both lines to have failed in the same manner , at the same time , but stranger things have happened with cars . Maybe one line is worse than the other , or the left line is just now failing causing the dragging feeling . This is the first that I've driven the car for a couple of years , so I haven't a clue as to how long the sticking brake issue has been going on . The pulling to the right has been going on for a couple of years now , but I don't recall the old boy complaining about the poor fuel mileage before this year . And trust me...I would have heard about it with fuel being @ $4.10 a gallon !

A little history.

This car started out in Wisconsin . I'm not sure how old the car was , or how many miles it had when the old boy bought it , but I think it was only a couple of years old . At this time it has 80K on the clock . It has become a real life 'only driven to church on Sunday' car . For the past 5 years (since it arrived on Maui) the car has been sitting outside for 6 - 7 months at a time . Then when the old folks return it gets driven once a week ( yup , to church ) until going back into storage again . I doubt the car has seen 500 miles of road in the past 5 years , and that just can't be good for a highway cruiser like the Eldorado . Now it also has developed a problem with the EGR system that keeps tripping the 'replace engine soon light' . The car seems to be seizing up a little bit more each day .

Thanks again ,

[Ranger]

I forget what the calipers where like on that year, but if it has pins that the caliper slides on, before they are lubed (with silicone brake lube) and rust free or they will not release. If the caliper rides on a machined pad milled into the control arm, be sure that is clean and rust free (unlikely).

[What job]

Thanks Ranger ,

I haven't had the time to do anything other than to see if the brakes were free after sitting a couple of days , and they were . When I put the car in neutral without applying the brakes , it rolled back with no problem . So I'm thing this is pressure related . The fluid is really dirty as well. Its hard to believe that the fluid could be so dirty. The car has had so little use since the fluid was last changed . Isn't over heating in the brake system one cause of dirty fluid ?

I haven't ruled out mechanical problems like the pads,or related parts binding . Hopefully I'll be able to muster the drive to pull the wheels this week end .

I do have another question . I noticed that the proportioning valves are two different line sizes . (10 mm and 13 mm ?) I can only locate one size, and no one knows the size of the line that fits it . Anyone have any input on where both valves could be found , or if one size could be made to work in both positions ? ( reduced fitting if valve with larger fitting is the one available? )

Having been in an R&D position for many years , I'm pretty sure there's a reason for the different sized valves . Manufacturers just don't add different parts when one part will work .

Thanks again .

[Dr.Fiero]

One reason (amongst others) that the fluid will go black, is from the seals braking down. Another is from air/water contamination.

I'm just going to guess and say that they/you've exceeded the recommended 2-3 years between full fluid flushes?

I'd be inclined to replace those front rubber lines, and do a total flush.

Not sure if this is stuff you do yourself or if you farm it out, so I won't go into details.

[BodybyFisher]

As others have suggested, don't overlook brake lines that "look" good on the outside.

They swell internally and block fluid flow, if its not the calipers or sliders sticking, I'd be looking at the hoses.