disc brake conversion kits????????????? expert opinions?

with T/A rotors and 85 k5 calipers theres iquite a gap the rototr is just under an inch and the gap between pads is 1 3/8 no fluid in it. is that normal? I was trying to avoid this, hence all the questions, Napa sold me calipers about the size of a fist, 85 k5 wouldnt line up to bracket. Carquest sold me 85 k5 about 10 inches and they line up. just thinking the gap is loose. Hubs fit to the rotors no mods needed just lugs.

Yes , the K5's seem to have a lot of gap without any exstension on the caliper piston. I raised my eyebrows at that also. I'm curious as to what runs out first ,the pads or the piston. The K5's use a 3/8 bolt on the brake hoses, I am under the assumption that the 3rd gens use a 7/16. I believe the 3/8's may open up a better hose selection without drilling out the hose ends as was mentioned in one of the "how-to" scenarios. Is is possible the K5 rotors are originally thicker? Is there a difference in measurement between the "ears" on the 3rd gen and the K5 calipers?

well ,by the on-line specs I have found the rotors are the same thickness. This is going to take me to the brake pads ? I bought the K5 pads to go with the calipers. A thicker outer pad would re-center the caliper better. its hard to tell in the pic but the caliper is already positioned over the allen bolt. Might be a good idea to go shopping again and see if the 3rd gen pads are thicker.

I hope to run lines today.. Most of my time is returning inncorrect parts. I mentioned this before I started, every part I got at Napa was wrong sept for the hand soap... I think when I say 65 the computor goes to 67?? I ordered a Griffin radiator called to check, 19x24 ..5 weeks later, 27x25.. so cut out a 2nd gen doghouse add crossmember, move sway bar connect electric and hoses to doghouse repaint.. all beacause of wrong part??/ I just returned it.

Yes, it is truly a learning and trial & error experience!!!! And Wdaguy, we've all done it, still are and always will be doing it as long as we have earlies. That's why it's called a "Labor of love" thing.....

** Great pic's Don!!!

I went out and got 75 g10 caliper..almost a twinn. but same problem the inside pad is riding on the rotor but the outs ide is flapping aaround..maybe 1/4 of play.. It seem like the rotor needs to go out? or caliper move inward toward engine? Any ideas??

try that again see inner pad rubbing outter is way off whats up?

that pad shouldnt be flapping around? and the other fitting sug? I am thinking with fluid its going to get worse??No? Anyway is there shimming or spacers needed? I am thinking maybe I did the bushings wrong so the rotor is is in too far? You are the boss I am just a painter.

I bought both 85 blazer and 75 g10 calipers..hard to tell the difference same issue with the pads.

I'm thinking it is going to be the nature of the beast, we are adapting parts not intended for our vans . I took mine apart agian today just to get another look and it will work as is. just not quite like one would like to see it maybe. the distance between the ears is the same 3", the only thing I can see to change the location of the caliper on the guide sleeve would be to space the rotor out a little further from the hub, but this wont change the gap in the pads, only thicker pads would do that. looks like the caliper piston will have to make up about a 1/4" like ya said WDA.
Also the ears on the brackets are very tight on the calipers , they need to be ground out so the caliper slides easily thru, (not even sure mine are good enough yet) if it gets warm it might sieze alittle. I have almost as many credit slips as part slips from the auto parts store, those guys at the parts counter have been very patient with me for the most part . Next thing I have to sort out is longer front shocks that are not fatter, Strike one there so far.

I just wrote a huge post about whats going on for you and the %$# thing disapeared when I went to post it.

I would like to help out here.

The brackets should have a 3/8 offset.

You might have a wheel bearing or hub problem.
tell me what bearings, hubs, rotors and calipers you are using?

Bolt the rotor to the hub and push the caliper in so the outside pad is up against the rotor then lets see a pictture of were the caliper eyelets sit on the slide pins. They should be about 1/16" from the brackets. dont worry about how loose the inside pad looks, that will go away when you punp up the pedal.

I am suprized to hear you say the rotors fit right onto the hubs, something aint right there. So far all 40 + installations have had to do a little re-work to the hubs.

What pads are you using? the more expensive pads are thinner. Get the cheep fully organic pads they are thicker.

The 79 trans am rear disc brake rotors are slightly thinner then the rotors used with those calipers.

The "K5" and the other calipers( same for novas, c series, g series 1/2 ton trucks (all) and most full size GM cars from about 70 to 78 )are all the same, the only difference is how the brake hose attaches. The all take the pads that have the basic part number of "728".
Those other calipers DONIVAN is measuring are from aN "S" series vehicle or rear calipers from alot of cars. They are the smaller calipers that take the pads with basic number 7070.

M1D

not to interject but i did NOT need to do any work to my hubs to fit the rotors using this setup with same rotor and calipers, etc.
so i guess that would make 2 installs without any hub work needed.
although i did expect to since everyone else needed it....
james

Well like my instructions said this is a frankenstien set up so no two vans will be the same.


as I recall There is an inner bearing race that will fit the hub but the bearing will sit about an eight of an inch lower and that will sit the rotor in that much further. I will have to consult my old research if I can find it. But I bet the problem has something to do with the inner wheel bearing.

Hey WDAGUY when the hubs installed does the nut land in the right sport just over the cotterpin hole when only one washer is used?

m1d

whenthe rotor and bracket are mounted it should have clearance like this







Why wont the pictures post?

M1D

Thanks for the help M!, always hate to bother you..
I went in another direction at first but have returned to the 81 T/A rear rotors
75 g10 calipers with 35.00 pads
with no fluid, the inner pads got 1/8 gap to disc
the outter has a good 1/4 gap or more and is rattling around freely.

I am concerned that when pumped up it will take a lot to get the outter engaged.
Bushings hubs ...did I do something wrong.. removed the stock hub ..had outter washer and small bearing but just the ball bearing part of the 2 part bearing.

Rear larger bearing only the ball bearing part was used and then a oil seal which layed flush to the hubs edge. this bolted back up is 1/8 inch from end of spindal. The hub sticks through the rotor about 1/4 of an inch..
I dont see how I could move the rotor out?

Sorry the hub went into the Nova rotors and the Trans Am with out any grinding. Making the master fit was a pain and then finding odd ball lines adapters is still going on right now. I will post more photos. I can check on cheap-thicker pads today. I dont do this for a living. So I dont know if the outter pad could be shimmed in or caliper spaced out toward the engine or maybe I am just worried about nothing? Keep me posted I respect your opinion Thanks Geoff

[size=18]The cotter pin did line up It could be one extra turn in more than befor.. I only replaced what I saw when I took it of. thought the 2 new bearing came in two parts the hub only excepts the angled part and a oilseal on rear..correct?[/size]

If you really have 1/8 and 1/4 gaps something is not rightThe gaps you are describing sound eccesive; Are you sure you have the right rotor? it shoulkd be almost an inch thick. I will take some more pictures of mine today.

http://vaninmag.homestead.com/discbrakeinstall.html

What bearing part numbers are you using? did you change the cone in your hubs? The cone is the angled part you have to press in and out of the hub.

The only shimming of the brake pads is an anti noise pad the comes with some pads.

The "good 1/4 or more is a problem as you will loose too much of the guide pin travel when you push the caliper outside pad up against the rotor. Which you can do and show us a picture. The out pad rattaling around is because you did not read the instructions. There is a "Crimping proceedure required that you will do with the pads you are keeping as they will not be returnable afterwards.





M1D