10 bolt Brake trouble

Johnson

Well-Known Member
Joined
Mar 9, 2007
Location
Mooresville, NC
I have chevy 10 bolt front end with disk brakes on it. The axle is under a Toyota Land Cursier. I don't no if it is 1/2 ton or 3/4 ton. I think I put 3/4 ton calipers on and my brakes will not keep preasure and stop up front, they work on the back drums fine. Is there a difference between 1/2 tun & 3/4 ton calipers. Like piston and fluid ammount? Also the front resivor will go down almost half way when I keep pressing on the brakes. Then it will fill back up. Need help thanks!
 
Many possibilities, could be a bad seal in the master cylinder, doubtful though. There are check balls in there, have you fooled with it at all? Are the calipers new or the master cylinder, could be a locked up caliper, but i second air in the lines. Tell more
 
what master cyl are you using ? stock toyota ? What year ?

which caliper will also matter

I think the issue you may be having is you aren't pushing enough fluid to make the caliper work effectively.

after you pump them up the fluid is there but is slowley moving back to the master cyl ( meaning you may also need a "residual valve" to help keep the fluid at the caliper )

Need to know what parts you have. Early Crusiers had drum brake on the front, later had disc, the disc system will have a residual valve built in. Drum system doesn't need it.

If using a GM master, and not the proportioning valve, this is also an issuem the residual valve is in the block of the proportioning valve in most setups.
 
Chevy ½ & ¾ ton calipers are the same 1 tons are alittle diff. Sounds like the proportion valve to me. $.02 :popcorn:
 
The land crusier is a 79 and it has the a new master on it. I have new 1/2 ton calipers, was going to try those see if helped. The 3/4 ton are on right now. What and where does the residuale valve do or go. My other thought since it was a chevy 10 bolt maybe I need bigger master since I am using land crusier for chevy stuff. But big thing is it was that way and working? Changed caliper and all went down from there. Can you bolt any bigger master to a stock crusier? Thanks
 
When you installed the new caliper, did you use new copper washers where the line attatches ? and is the line positioned correctly ? easy to misposition the line, and create an air leak, and not leak any fluid.

Must use NEW copper washers, only if you get REAL lucky will the old ones reseal.
 
calipers

is the bleeder screw at the top or the bottom of the caliper. i have known for calipers to be put on upside down, and you will never get all of the air out of the system, causing a very spongy pedal. doubt this is the case, but something to double check

good luck
 
blasterr1 said:
is the bleeder screw at the top or the bottom of the caliper. i have known for calipers to be put on upside down, and you will never get all of the air out of the system, causing a very spongy pedal. doubt this is the case, but something to double check
good luck
Click to expand...
LOL! I've done that twice. I made up new cuss words and threw a ton of stuff around the garage.:rolleyes:
 
those 1/2 ton calipers should be EXACTLY the same as the 3/4 tons you've got on there.

Did your cruiser have factory disk brakes up front, or did it come stock with drums?

I think it likely came with drums, and this would be good to know because that means your system is way undersized for the time being. Disks use MUCH larger pressures than drum-brakes, so you would need to get more pressure to those new front calipers to get 'em to work right. A new replacement-to-stock Master Cylinder isn't going to cut it, you need to push more fluid.

You're more than likely looking to find a bigger bore MC (~1 1/4") and maybe an adjustable proportioning valve and completely replace the stock one. This was what I did and it worked great. Not the cheapest, but the biggest time saver and allows for adjustment in case there's still some tuning to do.
 
So did your cruiser come with drums on all 4 corners?

I got my adjustable prop valve off eBay for about $40.

The best way to finding the right size larger MC is to know what you've got first. My 1 1/4" master cylinder came from a 1980 3/4 ton Chevy Suburban and was a direct fit into my '96 S-10 Master Cylinder location.

I didn't get any pics during the swap, but what you need to do is find out what bore you've got in there now to see if you need to increase it, then you'll have to figure out what will fit or what customization must commence.

Good luck!
 
Back
Top