M50 Swap, No brakes???!!

[KangamangusDriver]

I just completed my m50 swap including a new brake booster. My car has abs (1991 318IS) and the booster was from a 325IX. I have bled all the lines, numerous times using a vacum bleeder that uses compressed air.

Pedal feels slightly firmer after bleeding, start the car up pedal goes soft.
There is slight brake pressure but it is only on the front brakes.

I dont understand why there is no brake pressure after bleeding the brakes very thouroughly and properly.

Is there somthing im missing here??
Please help, very anxious to drive vehicle.

[BahnE30]

how do you bleed brakes with compressed air, thats the object to get the air out......

there's still air in there, did you bench bleed the master cylinder? are you still running ABS?

[arsevader]

how do you bleed brakes with compressed air, thats the object to get the air out......

there's still air in there, did you bench bleed the master cylinder? are you still running ABS?

He probably means he pressurized the fluid resevoir and bled them that way.

What you should be doing is checking the master cylinder for wear and lines and calipers for signes of leaks. Does the pedal go to the floor?

James

[KangamangusDriver]

The pedal goes to the floor and there are no leaks. How do I check the MC for wear/bad seals? Do you know if the MC from my M42 booster will work in the IX booster?

Thanks

[arsevader]

The pedal goes to the floor and there are no leaks

I would say that this pretty much points 100% to the master cylinder as long as you are sure nothing is leaking.

How do I check the MC for wear/bad seals?

Pretty much what you are doing. If it goes to the floor and there are no leaks then it's going to be the cylinder.

Do you know if the MC from my M42 booster will work in the IX booster?

I'm not sure about this one.

James

[KangamangusDriver]

thank you for your help

[rs4pro3]

Make sure you installed the Plastic check valve betweent he booster and the intake manifold the right direction.

[arsevader]

Make sure you installed the Plastic check valve betweent he booster and the intake manifold the right direction.

Good thing to check but a check valve installed the wrong way would cause a rock hard pedal as the booster would not be operating properly. It would not cause this problem.

James

[rs4pro3]

I had the valve in backwards when I swapped the m30 in and had the same problem. I thought I hadn't bled the brakes well enough, but flipped the valve around and brakes worked normally again. The booster is operated by Vacume, so with out any vacume pulling on the booster, The booster won't be able to help out the braking any.

[Brew]

did you bench bleed the master cylinder?

:?:

[nando]

ouch, how much did you pay for your new ix booster? AFAIk they are obscenely expensive! (~$500)

[arsevader]

I had the valve in backwards when I swapped the m30 in and had the same problem. I thought I hadn't bled the brakes well enough, but flipped the valve around and brakes worked normally again. The booster is operated by Vacume, so with out any vacume pulling on the booster, The booster won't be able to help out the braking any.

Exactly my point.

I don't know what the problem was with your brakes but a non operational booster would cause a hard pedal not a soft one.

James