1970s 75' eldo ride quality

[_Cap_]

alirght, ill go ahead and drop my PSI once i get the chance, ill drop it down to 32 and then see how it rides, if needed ill see about dropping it down to 28 depending on how it looks
thanks!
-Morgan

[The Tassie Devil(le)]

If you are going to continue at the high speeds, then you need to have a chat to a proper tyre shop for the correct information and tyres.

The stupid factory pressures for 1971 and 1972 were way too low, BUT, gave beautiful riding for anything below the Speed Limits.

Plus, if wanting to travel fast, you need to have the correct speed-rated tyres.

Don't forget that the Factory recommends increasing the pressure by 4psi when travelling at prolonged high speeds.   And I am pretty sure that the factory does not recommend exceeding the posted speed limits, even though the vehicle can easily exceed them.

Bruce.

[Big Fins]

I recently put a set of the Vogue 1.5" WW's on my Eldorado. The Toyo tires I took off I always kept at 40psi front and 35psi rear. The Vogue tires list 50psi on the sidewall as max psi. This supports the weight of the car better and gives the tread a nice even wear across it.

Running 28 and 24psi will have you riding smooth and replacing the tires in 10,000 miles due to edge wear. Whatever is listed on the sidewall of the tires is what I run and have never had any issues with tire wear. YMMV! It's your car, do what you want too.

[James Landi]

"The stupid factory pressures for 1971 and 1972 were way too low, BUT, gave beautiful riding for anything below the Speed Limits."

I always ran our '72 at those "stupid tire pressures" while cruising around our country roads... as Bruce states, (the factory tire specs")...gave beautiful riding." Indeed, the harshness of the suspension was dampened by the lower psi tire inflation.  Once the Eldorado was entirely redesigned in '79 and "downsized," it also received the kind of updated suspension so standard tire inflation did NOT degrade the ride.

[_Cap_]

alright, so yeah probably around 32 front, 30 rear is where i wanna be. I cant run Toyos and such just because of the money, i couldn't even tell you what brand im running right now. The goal is eventually afford some coker tires, but thats later on.
Ill mess around with the tire pressures, see which is the best. Im willing to bet its not my only problem. My suspension definitely needs bushings and such replaced sooner or later
I'm about to swap out the rear axle for the one on a 76 Eldorado I have in the yard. It has disk breaks so i want to go ahead and get that installed. Might as well nock the rear end out and change all the bushings on it

-Morgan

[TJ Hopland]

I personally would not do any sort of sustained highway speeds at 28, even at 32 the tires get pretty hot.  If you have an IR temp gun just try it.  Its quite a big temp increase for every PSI you drop and that can't be safe. 

As far as what the ride is like around 40 it depends on what you are used to and expecting.  If you are used to a modernish car that basically has no sidewall like a 60 series or shorter then 40 psi probably feels normal to you.  IF you drive a truck most of them ride like trucks too so again feels normal.  I like and want that land yacht feel where you don't really feel the railroad tracks and only know you went over them if you had the windows down and heard it.

The lower pressure lower life I don't really see as a huge problem with how often most of us drive these cars.  Age is usually the reason to replace tires and it just seems to get worse as time goes on.  They may be 'better' tires within their life of 5-7 years but at 8 it seems more often than not they are falling apart.  I'm not saying it was ever good to run say a 10-20 year old tire but I know we all have done it and it used to be fine.

In this case of being a daily driver things are a little different but if the lower pressure helps then perhaps that will just be the cost of comfort.  Buying new tires every couple of years is still cheaper than a car payment.


I'm not sure I have heard of anyone doing rear disc swap in these cars.  You could run into some issues up front.  The disc cars used hydroboost like the trucks and diesels so if you just order the MC from a 76-78 you would want to make sure the pushrod length and such all matches your vacuum booster.  You also have to wonder why they did the hydro boost?  Vacuum not giving the desired performance so if you don't also do the hydro will you not get the gains you are hoping for?  I think you really have to be careful with the amount of braking in the rear, it doesn't like to stay back there during heavy/panic braking. 

I would also assume the prop valve is different between the disc and drum cars so you will likely want to replace that too. On the drum cars it seems like at least under light braking it sends a little pressure to the rear before any goes to the front.  I'm not sure if this was a performance thing or maybe to just keep the car more level vs nose diving?  Don't want to spill your champagne like the peasants in their Fords and Chevs.  I don't recall noticing that delay when bleeding a rear disc car but its been a very long time. Maybe the delay was just due to drums and taking up the extra slack?

Also there is some little nugget in my brain about 75 axle being different in that it was a one year only that had some extra sway bar or something.  It may be that you can't put a 75 in anything else so you may be fine putting something else in the 75.   

[_Cap_]

thanks, yeah like you said its a trade off. As a daily drive tire wear is something to take into effect, same with highway speeds and opening her up every now and again. I don't have a temp gun but i do know someone who does so I might try barrowing it from them to see how my tire temperature behaves at different PSI

With the rear disk swap, I'm not really looking for any extra performance, but i do want the ease of changing out disk breaks over drums. Drum breaks are a nightmare to change and adjust. As far as i can tell the way my breaks are distributed is with a majority to the front wheels over the rear, 60 - 40 i think it is, might the more drastic then that.
I would love to also switch to the hydro boost breaks, I have all of the lines to do it with in the 76 eldo, however they only made a limited run of those boosters for i think 3 or 4 years. And I can only find 1 or 2 for sale online each for like $300. This puts me at a choice, since im going to be driving this car for a long time as a daily, I don't want any essential parts, I.E. breaks to be imposable to get if they go out. And they still sell rebuilt vacuum boosters for like $70 online, and there is a big stock because of how many cars they were used in, so for the time being they are really easy to get ahold of. If it wasn't for that problem I'd already have the hydro boost in my car

I did not know that thing about the extra sway bar, I guess ima have to jack both cars up and compare them, I figured it would be the same thing just different style hubs and a different end to the axle.  now that I think about it, im going to have to make sure the level ride system can hook up in the same place, It should be the same, the system looks the same, but now im unsure
Thanks for that information, might have just saved me a LOT of time

[TJ Hopland]

Have you worked with rear discs with the parking brake built into the caliper?  They are not as easy as a front ones and way less reliable.

Several years ago I was told by a shop that there are like 2 hydroboost rebuild kits that cover 90% of the boosters made for a 40 some year range so most of the time they are easy to rebuild.   

[_Cap_]

Ive worked with those kind so much as changing them out on a Miata, and yea they are a pain to get set right, but that miata also had very little adjustment for the parking break
I know i can get brand new calipers for it, and i believe its just a matter of setting up the parking break right? Like its a pain, but not near to the pain of drum breaks i would think.
Are you saying the parking break isn't as reliable as the drums?

I might try that, if i can rebuild the booster I already have then it might be worth switching over. I know a guy who actually might be able to find a kit to do that with

[TJ Hopland]

The calipers don't tend to be as reliable because of the added parts and seal involved in the parking brake.  Perhaps if you use it all the time on a daily driver they are more reliable?  I keep forgetting this is a daily driver.  Sitting and not using em are hard on em and they tend to get stuck.

The boosters are still used on the heavy light trucks and diesels so there are shops that rebuild them you just have to find one. 

   

[_Cap_]

ok, yeah that makes sense. Sitting does horrible things to any car, and i can see unused seals just going bad if not used consistently.
If i can get the better breaking from the hydro boost and the ease of changing breaks from the disk breaks that would be ideal. Ill see about getting one of those rebuilt kits and rebuilding the booster. It cant be that hard if I got all the right seals and such. Might have to get all of the rubber lines re-made however, that 76 was not kept in good condition and i don't trust those lines one bit.

and yeah its a daily, as in i take her to school, to town or just to go to a friends house. she's my only car and gets a lot more wear then most other classics now-a-days, but also means stuff stays in use and doesn't sit and go bad. The car was always like this, im the second owner of the car, the woman who owned it before me last titled it in 2016 and there is some evidence that she drove it consistently at least until 2005, which probably explains why explains why everything was still in pretty good condition when i got it, and the engine and transmission are still original and still running like a champ

["Cadillac Kid" Greg Surfas 15364]

FWIW my experience with Eldo rear brakes is that even the drum brakes will lock up with hard braking. There is so little weight on the rear end and much less when the car nose dives on a very hard stop. In the (something like) 500,00 miles I put on my '72 the rear brakes sasw so little wear I believe I changed the shoes 3 times.
Greg Surfas

[TJ Hopland]

I changed what I assume were original shoes in my 73 when I got it with around 50k on it.  I don't recall why, I'm thinking the lining had come loose or cracked on one side or the other.  Its now got like 120k that included some trailer towing and last time I checked there was still like 3/4 of the lining material left.   I too think they lock up fairly easily. 

[_Cap_]

Yeah my experience reflects that, with them locking up easily, sometimes even when you don't think your breaking that hard they just decide to. I bet the disk breaks will do the same. I'm just hoping the disks and the hydro boost can improve the breaking a bit. Everyone seems to always slam on there breaks last moment, and in newer cars that works out but in my boat its cut close sometimes, with the people in front of me slamming on their breaks at the sense of a turn

Also earlier today I was able to look under both cars and can say there is no difference in the axles. Sway bars and all are the same from what I saw. The axle off of the 76 was rusty as all hell and needs to be cleaned up a lot. Also needs new metal break-lines, but i figured that. The parking break system also looks very easy to swap out, as they connect to the main line in the same spot as on my 75.
The only thing i need now are calipers pads and rotors, and the seal kit for the hydro boost as well as new lines for that. Then its just a matter of re-building everything and swapping it over

[Big Fins]

Vehicles have brakes. B-R-A-K-E-S.

Break means to have something come apart.

[James Landi]

Cap,

My 72 with the discs up front and drums in the rear is, in my experience,  a very strong system--- If I apply the brakes hard, I can make the car skid.  Your original system might simply be old, out of adjustment and needing a total refresh.  I owned a '67 Eldo (daily) with drums all around, and it was frightening in a panic stop or a high speed slow down, so that I was always careful to leave enough room.  James

[The Tassie Devil(le)]

I too have pushed my '72 Eldo with stock brakes, and have never had a problem with them, even in panic stops, and hard braking.

But, I would be very wary of hitting the brakes at high speeds, like the ones you were referring to.

Plus, my car has the Track Master Brake option.   I found that my previous '72 Eldo Coupe also had the Track Master, and that saved my twice, once on a heavily cambered road, in the wet at a junction, and another time, on the highway, pulling off onto the verge, which put two wheels in the gravel, whilst the other two were on the bitumen.   Both times, the car stopped straight and true.   I didn't realise the car had the option, and was shocked just how good it was.   This made me look for that option when I was looking years later for the Convertible.

Bruce.

[_Cap_]

Alright, im looking for better breaking, but if it isn't really going to make that whole lotta difference then ill save my money and put it elsewhere. She still needs some body work to iron out rust spots, a paintjob and a new vinal top, plus a bunch of small things still anyways, and I need to rebuild a 500 engine and transmission soon to swap in her, and i know that's going to cost me a pretty penny

[_Cap_]

at the very least ill think about it, I still want to do the rear disk swap just for future proofing, even if it doesn't improve breaking. Might just put it off for a minute until i get my ducks in a row. The hydro boost system is still something i want, but again, lots of money into something that wont help a whole lot so probably going to push it all back until i got the spare cash for it