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Delta 88 68-70 front disc brake conversion - Parts acquired but help needed
Hello everyone ,
looking for some guidance as I start the process of converting my 68 delta from front drum to front disc.
I found what I believe is everything necessary to do the conversion off a 1970 delta 88 , however I do have a few questions.
1.) out of everything seen in the pictures what is readily available and cheaper to buy new then to have rebuilt? I know the booster will have to be rebuilt because you cannot find those but what options are out there for front disc/rear drum master cylinders that will mate to this booster . I see a bunch on rock auto.
2.) Does anybody know where I can get new calipers and rotors ? Or if you can ? Seem to be hard to come buy . If I’m stuck with these , are the calipers able to be rebuilt and rotors turned ?
3.) is the proportioning valve something that needs to be rebuilt or is that good to go ?
4.) from what I understand I should be able to maintain the factory speedo with these spindles . Any tips or tricks with that ?
5.) who’s the best in the business for a rebuild service for the booster etc..
any and all Info on how to complete this process would be great
Those are actually 69-70. The 67-68 use the four piston calipers. New calipers are readily available, just be sure you get the ones for the 1.25" thick rotors and not the more common A-body calipers for the 1" thick rotors. Note that unlike the A-body cars, the full size disc brake cars of this vintage DID use a prop valve. It was located down on the frame in the line going to the rear brakes. You'll want some sort of prop valve in that line, probably an aftermarket adjustable one. You could also replace the metering valve and distribution block with an aftermarket combo valve, but the Chinesium PV2 valves have a pretty spotty quality record. The metering valve is available new, and you can also get a rebuild kit for your old one. Replacement M/C is also available new.
The one thing you can't get is new rotors. I've adapted the rotors for a 2003-2006 Caddy CTS by opening up the center bore and redrilling the lug holes. All other dimensions are nearly identical to the OEM rotors. Raybestos 580120NZ is what I used.
could you please tell me what these two parts are just to make sure I got it right, if I could re-use them , and if not where could I find. Also could you tell me which master cylinder is the right one .?
Looks like they are out of stock everywhere. You can rebuild yours. The advantage of the single piston design is that the sealing surface is on the piston, not in the bore, so if the piston is pitted, you can replace it.
Zabbs22
Just a quick echo to say
1) Disc brake upgrade is a worthy undertaking. Everything these days stops better than ‘60’s cars.
2) Joe’s steering you exactly right. Follow his advice and you’ll have the best solution any of us know of.
3) You can use an adjustable Willwood proportioning valve mounted to the driver’s side frame rail more or less anywhere along the length of the line from front to rear; seek Joe P’s guidance on adjusting it.
4) Go for 70 calipers if you can find them, but in a pinch ‘71 single piston calipers can be made to work with just a bit of grinding
5) The stock GM distribution block from ‘70 has an electrical connection in case of pressure loss - I wired mine to my emergency brake light. The idea is that if lights up when the car is moving you know you have a brake problem, otherwise the e-brake light works normally.
6) If you can find a master cylinder that exits on the passenger/engine side as opposed to the inner fender side, you may have more room to fit pipes. This could be a feature of my ‘66’s, your 68 inner fenders may not be a problem. I had “clearance” mine with a BFH and it’s tighter than I’d like.
7) The Cadillac conversion / adaptation works. I’ve done it on my ‘66 Starfire. But the machining has to be right or it can pulse & squeak. I wound up getting 3 sets of Caddy rotors and having them machined to work on ‘70 hubs since rotors are essentially service parts. Just to put it out there, if you can find additional ’70 hubs, even if the rotors are under spec (I think thinner than 1.215”) _grab_the_hubs_.
8) While you’re at it, I’m guessing you’ll replace the rubber hoses and do the other safety basics like rear hydraulic cylinders, shoes, springs, etc.
Yes, that's pretty much how you do it. It's a trial and error process. Be aware that the optimum balance also depends on weight distribution. This is why pickup trucks frequently have an adjustable prop valve above the rear axle that changes the balance in response to ride height (which is a function of load in the bed).
This is very interesting topic. I'd like to convert drums to disks to my 68 Delmont. But living here in the middle of nowhere in northern Finland, there are no junkyards to find parts. Is it possible to find new spindles and hubs? I know, i can buy rotos (Caddy) from Rockauto..
This is very interesting topic. I'd like to convert drums to disks to my 68 Delmont. But living here in the middle of nowhere in northern Finland, there are no junkyards to find parts. Is it possible to find new spindles and hubs? I know, i can buy rotos (Caddy) from Rockauto..
Considering that no one makes rotors for these cars, which are normal wear items, there is even less of a business case to be made for making new spindles, so no, not even close. Good used are the only option here.
Considering that no one makes rotors for these cars, which are normal wear items, there is even less of a business case to be made for making new spindles, so no, not even close. Good used are the only option here.
Thanks Joe
I found this when searching internet. It's for 1970 fullsize Olds. Wonder if it fits
Your first warning should be the fact that the ad claims these fit 1967 through 1972. The 1971-76 full size cars are completely different and NOTHING interchanges with the 65-70 cars as far as brakes or spindles or steering are concerned.
Also, do a search on the part number for that kit. Note that the bolt pattern shows 5 x 4.75", NOT the 5x5" pattern used on the full size cars. Run, don't walk away. As is nearly always the case, vendors get applications wrong for Oldsmobiles, ESPECIALLY on cars that aren't A-body cars. This kit is probably for a Chevy Impala, which shares exactly NOTHING with an Olds full size.
