1984 eldorado disc brake help or info

Started by paul, March 21, 2009, 07:04:46 PM

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paul

I have a 84 eldorado coupe 4100 fuel injection. The car has rear disc brakes. when i  aquired car had no power assist. poor if any brakes. I bled out entire system. made sure front and rear calipers are free and are working. replaced power booster with a used one from a seville. Now have power assist car stops much better but still have brake light on and pedal travels very low and feels spongy.  Im going to try to bleed rear brakes again tomorrow. pads were good front and rear. has anyone experienced this with this car? Its my first early eightys eldorado. i dont want to start replacing parts. i do have a proportioning valve used from my 83 seville parts car if needed and can get a bew master but the master isi not loosing fluid and was pushing out ok when was bleeding before. Any help or tips .

The Tassie Devil(le)

G'day Paul,

By "Brake Light" I take it you are referring to the Brake Warning Light on the Dash Board?

Once the warning light has been illuminated, it will stay that way until the leak has been fixed and the switch been "Re-set" to turn off the Warning Light.   I am not sure what method is used by Cadillac, but in most vehiclers I have worked on, it is simply a matter of removing the switch, and reinstalling it.

But, as you are aware, when bleeding brakes, one has to bleed each line from the furthest point away from the Master Cylinder, and working back to the closest.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

paul

The brake light usually goes out when the systen is properly bled. My main question is were these brakes on these particular cars with the early rear disc brakes troublesom. On fellow who worked at a dealer told me that when the car were new people complained of the soft pedal and the inability to stop short. Im wondering if anyone else had heard or experienced this? as that is what im having now.

Roger H

The proportioning valve can be "tripped when bleeding if you are not careful.
The valve will move to block off a set of lines if large fluid loss is happening (such as when you are bleeding and you mash the pedal all the way down with the rear bleed valve open.)  When bleeding you need to push softly and only go 1/2 way down never mash to the floor.  To reset the valve, if it was tripped in the rear section for example.  Have an assistant press  on the pedal as you open a front bleeder and get it to recenter.  The proportioning valve is just a spool valve that moves to block off brake line passages in case a brake line breaks.

The brake light can be turned on however from low fluid or parking brake also.


Roger
Roger Hundtoft
1936 Fleetwood 8509
Lynnwood Wa

paul

I got tip from a parts supply man about early brake pads that were used on those cars. When the world went crazy and the government mandated that organic brake pads be used instead of the tried and true asbestos type , this had a negetive effect of braking quality across the line. As a mechanic i rememer how lousy those brake shoes and pads were. They wore out fast and heated up rather quickly and ate up rotors and drums. The metalic pad technology has come along way since. This car has just about 50,000 old lady  miles on it and im wondering if these are original rear pads. They are very white in color as i remember those organic ones to be. I have beled thisi system out over and over . I still have the light and im starting to think its a defect in the light itself . We changed the power booster and it has a good power assist now and seems to stop much better. Im thinking of changing those rear pads to a good quality metallic up to date type and see if it stops better. ill keep you posted

Guidematic


There are 3 things that can turn on the brake light on those cars. 2 of which you are likely familiar with, low brake fluid pressure in one of the circuits and the park brake.

The other is a low vacuum warning. There is a sensor in the booster that senses low vacuum and turns on the light. These cars use a vacuum pump and a myriad of steel vacuum lines that supply vacuum. Also check the filter/check valve in the system for proper operation.

Also, the calipers themselves were problematic. There is a ratchet assembly that compensates for brake pad were so that the parking brake stays adjusted. This ratchet will seize up and leave you with a low pedal, even if the pads are in good shape.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

paul

heres what i have found so far. today i actually got into it. The emergency brake cables are free and the ratchet arm moves when you. put the emergency brake down , But the pads do not contact the rotor. I was told that the trick to keeping these brakes in adjustment was to always put the emergecy brake down every time you park the car. This makes sense as the piston only ratchets out so far when you press the pedal. To remove caliper after you take the standard bolts out you need to disconnect the actual steel line fron the caliper brake block. Mine broke so i will replace bolth steel lines when i reassemble. Then you take a chisel and spread the gap where the cable and the end of the cable hooks to the adjuster arm so that you can slide the emergency brake cable out . Then you take a flat screw driver and compress the spring so it exposes where the emergency brake cable stays or fingers show . Then take another flat screw driver and push in on each of these tang stays and the cable will slide out. Now you can take the whole caliper to a bench vice and work on it. I bought one of those standard caliper ratchet tools but it does not work on this caliper. There must have been a special one so i took a old large pipe wrench and turned it in with that. You can use large channel locks . I as usual could not find mine. Be careful and gentle as the piston alumanum is soft and the brake pad spring fits in a grove at the leading edge. Be gentile. The piston turn in counter clock wise and ratchets out clock wise. I went both ways a few times to be sure it was good and free. It was. No sense in buying new calipers if they are fine. . Tomorrow i will test the ratchet arm and make sure it ratchets out the caliper piston. i had no penitrating oil and i did not want to rush the job. Plus the round guide pins that sit in the rubber that the long fastening bolts go through were seized to the rubber. i broke one trying to drive it out . My son isi going to see if he can buy 4 new ones . if not ill clean up the one i have and dig through some of the old calipers i have laying around. Thats the least of my worrys. I will never seize he hell out of everything when i reassemble it. I will keep you posted. After thisi isi all done if the light isi still on i will check that vaccume pump and all the plumbing involved. We did change the power booster because it was blowing out the back side when you hit the brakes. Thisi one was used out of a seville but appears to hold vacumme even when the car is shut off and you hit the brakes 3 times . so i do belive the power assist isi functioning at least at the booster. Thank you all for your tips and keep them coming.

Guidematic


What you have told me about the function of the parking brake and how it does not contact the rotor suggests that the calipers do need replacement. The ratchets in the pistons are not functioning to allow the pads to stay in contact with the rotors, creating a long apply stoke and the low pedal.

Yes, it is good practice to use the parking brake each time you park the car. This keeps the system functioning well.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

paul

OK The pads were worn down to the end. the new pads are much thicker. I sprayed the ratchets and got them moving . The caliper piston does move now when you work the ratchet arm. I am conident that the calipers are ok to use , they were just in a state of neglect from not being used and serviced with a combination of buffalo area climate. The left caliper turns in counter clock wise the right turns in clockwise. I am a fixer and ive spent a lot of  time playing with these because its my kids car and his budget is limited + its been a learning experience for bolth of us. Im more of a 50s 60s and 70s cadillac mechanic. I didnt much care for down sizing and government mandated cadillacs of post 1976 . But now as time has gone by some of them and thier style is appealing. In my mind the old boats of yesteryear will alway be the true image of cadillac. But to each his own., I have one more question.  i didnt pay attention to the inside pad that goes up against the caliper. There is what looks like a anti rattle clip that goes around the lip of the caliper. On the back of the pad there is what looks like a centering tab at the lower portion. there is a deep square slot on the caliper piston face. does this tab on the back of the pad sit in that square or does it have to be 180 degress the other way? If it sits in that square it cant ratchet out im thinking it will lock into place. The face of the piston has a evenly spread out series of indentations. It dosent seem that the pad would sit on the piston straight if one goes that route. Im ready to reassemble this mess tomorrow and i dont want to screw this up. I will tell you this im becomeing a expert fast.  If i can get this back together right and functioning ,then if anything isnt right i can honestly say ive ruled this and that out and can replace things that may truly be defective. I know from what ive heard about the brakes on these particular car, but it will have to stop a heck of a lot better than it did whewn we first got it. Again thank you for your help. Maybe theres someone else out there blindly going through the same thing i am and this will make it easyer for them .

35-709

Next thing you want to do, if you haven't already, is to get VERY familiar with the care and feeding of that 4100 engine!
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

paul

I am very familiar with the engine. I had a 82 sedan deville that had 150,000 miles on it. The woman i bought it from had it rebuilt at 130, 00. I drove that car without a bit of trouble to just over 200,000 less a water pump. Then the trans went. i replaced it with a junkyard one that was on its way out and got another 10,000 out of it. It was great car for what it was. no wheres near the quality of the mark that made the name but it got me around reliably. No power but im not a hot rodder. This engine in this eldo has just over 50,000 miles on it, im hoping that it had the leaks and motor gremlins worked out of it in the early years. Seems to run fine . No milky residue under the oil cap. I think my boy will like it and hopefully his next ride will be a 60s or 70s cad. I got a 82 seadn and a 83 seville for parts so some of hat hard to find stuff may be at my desposal if needed. Ive been told to stay away from these cars like they were the plague from some. I guess im a glutton for punishment. They are a very nicely syled car though . Ill keep you posted on her ailments and remedys . Im glad there is a forum like this that offers adice and tech tips. I think once this brack problem is resovled it will be time to take it to the road and bring out the rest of the bugs. LOL

paul

Well today i got the rear brakes all put back together. THe emergency brake holds the car when its applied and put into drive. So i took the car down the road for the first time. The motor runs very well and the transmission shifts beautifully. The car stops good but the front rotors were pulsating and warped from most likely being heated up and being the only brakes that were functioning when the car was on the road. So i got new rotors and pads at the parts store. I AM determined. My kid drove the car on the way back from the test drive and was in love with the smoothness and that big car feel and ride. So tomorrow i will do the front brakes. I also ordered a transmission filter and gasket and will change that. No sence in having the car up and not doing it. A ounce of prevention i tell the boy. My son bought this car and pays for all the parts with his own money. I supply the labor and the education ( i seem to be getting one myself) He is hands on and learning right along with me. . I look at it as there will be one more old car mechanic to carry the torch for the hobby and the future. I will keep you posted . Thanks again for the tips.

homeonprunehill

PAUL ,Iam a littlebit fuzzy on the ELDO not having ever owened one, but have owened an '86 and 71sdvs and I thank that relacing the wheel NASCARE Style wil cause the plusating when applying the brakes. THE TIRE SHOPS will tell you that they used "torque-sticks"to torque the  "lug-nuts", but they still  torque them NASCAR STYLE!!! Once a rotor is "warped", no amount of torque will get them straight-again, I'LL TELL you how I torque log-nuts. Lets just for fun, say that the required torque is 100 ft lbs. Div. by 3 . Let your boy pull 40 lbs on the first pull, cross toquring all of the time (Very importent to cross torque.) then you do the second pull, applying another 30l.bs then let youre son pull the last 30 lbs. (To cross  torque, torque oposite lugs each time.) HTH,Jim
USED,ABUSED AND MISUSED CADILLACS AND LA SALLES

Guidematic


Paul,

There is no way to reach the ratchet mechanism externally on the caliper. It's internal to the piston.

By replacing the pads, you have reset to calipers and taken up the clearance from the worn old pads. Maybe the system will work OK now, but in my experience, they never return to normal function with a simple pad replacement. As the pads wear, the pedal will drop further to the floor.

This was a very common problem with all GM cars with 4-wheel disc brakes in this era, and it even sparked a recall with manual shift Camaros, Firebirds and Fieros since the parking brake would not hold. I was decreed a safety issue and a product campaign was issued.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

paul

To reply to the first comment on tightening lugs. i have owned driven and serviced extensively every year cadillac from 1952 to 78 and a couple 80s ones. i have never seen a rotor warp other than from excessive overheating either by a stuck caliper or by seized rear wheel cylinders  and over heating of the fronts . I have used impact wrenches and breaker bars . I always cross tighten and gradually. Never had a drum or rotor warp because of it.  To answer the second question . I bench vice tested these rear calipers. As i worked the adjuster arms to get them moving like they should the pistons came out a good 2 inches. i screwed them back in and repeated the process a few more times . the calipers although used are working fine. Like i said the emergency brake held the car when put into gear. At a inspection shop that is king. It poured all day today so i havent had a chance to do front brakes . But from my experience one of those rotors is warped from over heating maybe a caliper was sticking . ill determine that by how even the brake pad were wearing and how much pressure it taked to push them back in. Im hoping it was from over heATING from running on front brakes only and a good cleaning and surface sanding of the moving parts and a generous helping of never seize will be all the calipers need. I wont know till i get in there. Might even need brake hoses if they are dry or damaged . Thank you ! I dont know everything and i appreciate all the help i can be given.

paul

Mike i misunderstood your responce. Yes i have heard that. As the pads wear the pedal will get softer and softer. Ive heard that the brakes on these cars are a nightmare. One thing i also heard was that if you use the emergeny brake all the time when you park it it ratchets the pads out and keeps them in adjustment with the rotor. that isi howo you keep them in adjustment kind of like when you back a car up with rear drum brake adjusters . thats why you have to screw them back in because the internal adjuster cranksk them out and takes up the slack. That emergency brake is what ratchets them out and keeps them in adjustment. So i heard. Ive heard alot more about howo crummy the brakes are on these cars . I guess ill find soon . Once the car is right enough to go on the road.

Guidematic


Paul,

Yes, the calipers may work fine on the bench, and the pistons will come out as the lever is moved.

But, when the system works right, the brakes are excellent on these cars. Reman calipers are still available for a reasonable cost, except that they have a nasty core charge.

I currently have a 1988 Eldorado that has 4-wheel discs. It uses the same design calipers andd thus far I have no trouble with the brakes on this car. The car stops very well and the pedal is very firm.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

paul

Just a update. We did the front brakes. New rotors, new caliper hardware (rubbers, pad clips and mounting bolts) I showed the bow the importance of sanding all surfaces that the caliper moves on and to use never seize every time you service brakes. Especially in this northern NY climate where salt and aqs of latly very corrosive additives from the bottom of beer vats are being mixed with winter road salt. Now the brake like problem is eliminated. The pads were worn to the rivets and rotors shot. Thisi brake system was in total neglect prior to my sons purchace. We changed the transmission fluid and filter. I show him the importance of clean surfaces and to peen the pan bolt holes and check for warping. I also stressed that overuse of silicone cement could cause transmission faliure and we only used it on the bolt threads. The clened surfaces produced a good seal and a professional look without goop protruding from the gasket seal. We took the car for a ride and that car stopped just fine. We were bolth happy. The engine rund great but as i told the boy it will not have the pep of his 89. The trans shifted equally nice. The boy was so excited that he went out and bought new rotors for the rear. so we will replace those this weak. The old ones were ok but this kid insisted. So now everything will be new and im thinking he will put this car back into service in the coming weeks. His 89 fleetwood coupe was wrecked thisi winter when he slid off the road and broadsided a tree. i put it back together for him enough to continue driving it but it will not pass inspection this june . A shame because it was such a pretty car and he cared for it well. But he has been bitten like his dad. It will always be one cadillac after another in a life time persute to have owned them all.

EldoradoRedd1

Hey Paul i'm glad u posted some info on the brake system f/the Eldorado. My '80 has that spongy feel to it also so i'm gonna hav the mechanic check my rotors
the whole system. This is a very informative topic
S.Rhame

paul

I thought ide give a update on this car. My son has been driving it now for about 3 weeks a month. He is absolutely in love with this car. He has no complaints about how the car stops and claims that the more he drives it the better the 4100 V8 performs . The car has now been reliable for over 1000 miles. Thats not alot but the boy has taken a few more than a hundred mile trips with out incident. I know i have heard how terrible these cars were when they were new but i have to say this, 25 years later all these early problems have and can be solved with regular maintainance. These cars were cars that were tempermental and experimental at a time when you were used to getting longer periods of service out of less maintence.  Aside from the engine problems these were good cars. Better than what we have today in structural quality and the pure driving please. This ofcourse is my opinion, im sure other will disagree. But the driving experience and the ride was what cadillac was all about . And these car still had that. They are as much a pleasure to drive today as they were 25 years ago and 50 + years ago. Thats whats lacking in todays cars for all the technology we have we forgot to design in person style and enjoyabilty of the driving experience. To me how good a car is equates to how much you never get tired of driving it. thanks