Another disk brake thread

[Mikel]

There is mid 70's Eldorado at my local junkyard. I'm tempted to graft the front and rear brakes into my '66 Toro. I have read Mark Pruett's write up and it is pretty clear that the old drum brake wheels do not fit over the stock calipers. I am wondering, how bad is the interference?

Also, any point in using the hydroboost from the Eldorado? Any advantages over the factory booster (I would use a two piston MC).

[Twilight Fenrir]

There is mid 70's Eldorado at my local junkyard. I'm tempted to graft the front and rear brakes into my '66 Toro. I have read Mark Pruett's write up and it is pretty clear that the old drum brake wheels do not fit over the stock calipers. I am wondering, how bad is the interference?

Also, any point in using the hydroboost from the Eldorado? Any advantages over the factory booster (I would use a two piston MC).

Well... Nothing I have to say is necessarily accurate, it is, however, to the best of my knowledge.

I recently found some spacer rings on eBay that are supposed to alow you to use drum wheels on disc brakes... They are listed as fitting a '66 toro, but I'd take that with a great big spoonfull of skepticism.

As for the booster, as I understand, the factory booster will not work with disc brakes. I just bought everything I need to convert my front brakes on my '66. The only thing I don't have is the wheels.

I found a pair of '69 knuckles on eBay, and ordered everything else brand new, or rebuilt from Rockauto. Using a toro from the same generation, all I needed from the salvage yard was the knuckles. The only thing I didn't find on Rockauto is the proportioning valve, which I had to get from oReily's. Haven't actually done the conversion yet, as I am still finding wheels. It only ran me about $600, plus whatever I wind up getting some chrome '67-70 disc wheels for.

This is the very, very best writeup for disc brake conversions on our 1st gens. It covers alot of data, and the process.

http://www.breznick.com/toronado/brakes/index.htm

He also has a fantastic writeup on wheels, for the curious.

http://www.breznick.com/toronado/wheels/index.htm

[69W34]

"I recently found some spacer rings on eBay that are supposed to alow you to use drum wheels on disc brakes... They are listed as fitting a '66 toro, but I'd take that with a great big spoonfull of skepticism. "

This spacer will not work the 66-67 drum wheel can not be made to accommodate disc brakes, any spacer would off set wheel center line so much it would stress the wheel bearing not to mention looking like hot wheels. Trust me if it were possible to been done it would have done by now.

"Also, any point in using the hydroboost from the Eldorado? Any advantages over the factory booster (I would use a two piston MC)."

The hydro-boost is an absolute necessity it is part and parcel of the four wheel disc system.
MP's article should cover this in depth.

[Mikel]

If I use all of the '76 Eldorado suspension, can I retain the Eldo axleshafts... Will they bolt to my '66 TH425 diff? Since '66 axleshafts are hard to find, this might be a good thing to switch to. Thanks.

[68 Toro]

Thank you so much for your kind words about my Toronado disc brake conversion website. The disc brakes on the Toronado have functioned flawlessly since that installation (September 2005), except that I had to replace the master cylinder last year due to its total failure (March 2010). Here is the story and lesson that I learned from that experience.

As I was driving home from work one day, I applied the brakes and heard a muffled "pop . . . pop". The brake pedal went all the way to the floor. Stopping power was about 10% of normal. As it was the early afternoon, I changed directions and headed to the closest auto repair facility, driving very slowly (sorry to all those driving behind me that day).

The Goodyear Auto Service Center mechanic determined that the master cylinder was unrepairable, and he would call around for a new remanufactured one locally. I called my wife to pick me up. As the long-suffering spouse of a Generation One Toronado owner, she was used to this kind of thing.

An hour or two later I received an urgent call from Goodyear asking me to clarify what model year was my Toronado. Apparently they has installed a master cylinder for a 1968 Toronado, bled the lines and everything, but the newly installed unit would not function. Sheepishly I told them to order a 1975 Toronado master cylinder. Obviously I had forgotten to explain the disc brake conversion when I dropped off the car, and the crucially important fact that all these components including the master cylinder were from a mid-1970s Toronado donor car.

They removed the '68 master cylinder and installed a '75 master cylinder. Everything now worked, but I was charged double for the labor (fortunately the incorrect part was cleaned up and returned for full credit). A very expensive lesson learned.

$ 45 master cylinder
$ 182 installation
-$45 credit for incorrect part
$ 45 master cylinder # 2
$ 182 installation # 2
$ 93 brake fluid
_____
$ 502

[Chazzer]

Interesting stuff David, thanks for sharing. I've often wondered what your long term perception was concerning the conversion. Was it worth it? How much difference noticed in braking power, that sort of thing.

I have everything to convert mine but have not done so yet.

Cheers, Jim

[68 Toro]

That's an excellent question Chazzer! I remain extremely happy for having undertaken this complex upgrade. Although I never quantitated the stopping ability before and after the conversion, my feeling is that it improved dramatically. Of course that might be a false reality as no data was ever recorded. But my confidence in the Toronado's capabilities increased to the extent that afterwards I began to drive it substantially further away from my home, and at greater highway speeds. This increased my Toronado's utility as well as the pleasure I derived from driving it.

Also, this was a first-hand learning experience that will persist with me forever. Not only do I feel like I've become somewhat of an expert in an narrow topic, but also I have plenty to enthusiastically describe and show to interested others. Maybe a "world-renown" expert!

[xgecko]

This is an interesting question - the OP question - that I am about to be in a position to answer.

I am finding that the Mondell JM 20-22 cam is a bit too aggressive for the vacuum power booster even though they claim it will work. Perhaps because we cannot put headers on the car; not totally sure why but I do know I am only pulling about 12" Hg on the vacuum meter and braking takes substantial effort.

Long term goal is to upgrade the rear drums to Eldorado disks just like the OP stated, so I bought a '78 Eldo for parts which I am now very happy I did... I tried ordering the Hydroboost unit from local parts stores and they are all out of stock with no ship date. I wanted a new unit, but a working used unit is better than no unit.

I will be pulling the power booster today or tomorrow and grafting it along with the power steering box into my '69 this weekend. Once this is done the car will be quite drivable.

So in answer to the OP writers question, this all should work out and allow the eventual upgrade of the rear brakes to disk. It also will eliminate any issues with vacuum regarding brakes.

[xgecko]

On the Hydroboost upgrade...

I am very happy with the result. Incredible braking performance with rock solid feel. Low vacuum issue is now a non-issue.

Cons: You will have to find a way to provide some clearance around the exhaust pipe as the Hydroboost has an accumulator that is almost touching the exhaust pipe. I was installing new exhaust so I just whacked it a bit flat with a hammer and it seems fine. I also removed the original metal heat shield and replaced it with DEI header wrap. You will also want to make sure the MC is matched to the booster as the actuator rod needs to contact the MC properly. I just went with both from my 78 Eldo parts car.

I would do it again in a heartbeat, and I will do it on all the classic cars I eventually hope to own. Much like upgrading the alternator or power steering box, this will have a meaningful impact on the driving experience.