Topic: Weak brakes

[Burl]

I've developed this braking problem on my 85 runner.  When I first built the rig it was a bone stock automatic then I converted it to manual.  I upgraded to the larger brake master cylinder about a year ago and it has been pretty good.  Lately the front brakes have been engaging automatically causing them to drag which is a serious power loss.  I talked to dave a marlin and he consulted with Marlin about this, and suggested that my pedal didn't have enough free pedal which caused the return for the brakes to be partially blocked not allowing the pressurized fluid to escape once pressurized.  I backed the pedal off a little and now the brakes are very weak, so weak that I don't feel comfortable driving it over about 25mph.  I still have stock front and rear brakes which might not be very compatable with the new master cylinder.  If anyone could give some more advice on my brakes I would be very appreciative.

[Tallchevy]

Try a stock MC & see what it does.

[emsvitil]

The calipers could be getting sticky and not retracting

(My left front does this every once in awhile, need to take it off and get a freebie (lifetime warranty))

Usually only 1 will stick.     Take your hands off the wheel and see which way if it pulls.    The side it pulls to is usually the good side (not overheating and braking ability).    Also the bad side will probably have more brake dust.........

Braking force is a product of the ratio of the areas of the calipers vs master cylinder bore size.   A larger bore gives you a harder pedal (more leg needed) with shorter travel.   A smaller bore is easier on the leg, but more pedal travel.

You also may have boiled some fluid due to sticky calipers which will make things mushy.....

[Burl [OP]]

I'll try this since thought my old one worked pretty good before I did the upgrade, I just thought that if I did the upgrade the brakes would be even better.

Try a stock MC & see what it does.

[Burl [OP]]

Was considering buying the V6 front brake kit from Marlin today just because.  All though my front calipers are only about 3 years old.  I will probably try a power booster as well.

The calipers could be getting sticky and not retracting

(My left front does this every once in awhile, need to take it off and get a freebie (lifetime warranty))

Usually only 1 will stick.     Take your hands off the wheel and see which way if it pulls.    The side it pulls to is usually the good side (not overheating and braking ability).    Also the bad side will probably have more brake dust.........

Braking force is a product of the ratio of the areas of the calipers vs master cylinder bore size.   A larger bore gives you a harder pedal (more leg needed) with shorter travel.   A smaller bore is easier on the leg, but more pedal travel.

You also may have boiled some fluid due to sticky calipers which will make things mushy.....

[Burl [OP]]

So I went to marlin today and got some more advice from the pros and was enlightened that stocker brakes are not very compatable with and oversized master cylinder.  I purchased the v6 calipers and performance rotors this should fix.

[Burl [OP]]

Got the V6 brakes and upgraded rotors installed yesterday.  Brakes work really good.  Also installed the backing plate eliminator at the same time looks pretty good.  While I was tac welding the brake line tabs I mounted the rock sliders that have been ready for over a year just never got around to doing it.