Axle Swap - Brakes

[AZ79K5Project]

I replaced my front axle last weekend after replacing the rear. Rear - new brake cylinders, new springs, old (still new) shoes and drums. No problems. Bled the brakes - tested - like new.

Front axle: Donor - 87 10 bolt. Replaced the 79 front axle.

I replaced the front calipers and front brake hoses for steal braided/extended lines. The front lines remained open for an extended time during the swap.

Problem: I can't get brake pressure. I bled the system. I still get a mushy peddle. The truck stops and has brakes, but they don't have the stopping power. Any ideas????

The calipers for the 87 and 79 are different part numbers. I thought all 10 bolts were the same until 89 to 90 when they changed to 30 spline shafts. The 79's bolt up, but they don't look like they are seated properly.

What are the differences between 79 and 87? Is the difference due to the axle being different or are they matched to the MC pressure/flow for that model year?

Thanks

 

[4X4HIGH]

The brake lines are different between D44 and 10 bolt. The D44 uses a 7/16" banjo bolt whereas the 10 bolt uses a 10mm banjo bolt.

Which brake lines did you buy, for what year?

 

[AZ79K5Project]

Both axles are 10 bolts. Banjo bolts - new, no problems no leaks. I purchased the lines off from Summit. They are for model years 79 through 91. Brake Line

EDIT: They are Skyjacker brand.

 

[4X4HIGH]

Well, FWIW i had to grind on the block of the brake line to get it to seat properly on the caliper when i installed mine. Mine didn't leak but they did suck air into the system until i finally figured out what was going on and ground the block for them to seat correctly.

 

[AZ79K5Project]

Well, FWIW i had to grind on the block of the brake line to get it to seat properly on the caliper when i installed mine. Mine didn't leak but they did suck air into the system until i finally figured out what was going on and ground the block for them to seat correctly.

"Block" - Are you talking near the base of the caliper itself? I ground both as well to get them seated and to get the bolt holes lined up and EDIT: the caliper body not hitting the spindle housing.