Flare On Brake Line

[Akula69]

Working on the brake system on the MJ and have a question.

 

I have retained the MJ proportioning valve but have replaced the mater cylinder and power booster. Bending new lines now and wondered if anyone knew: Does the MJ prop valve used bubble flares or double flares, and how could one tell? What flare does the XJ prop valve use?

 

The reason I ask is, after searching the threads here in the forum, I have found conflicting results.

 

Thanks!

 

 

[HOrnbrod]

The MJ proportioning valve is the load sensing valve on the axle. The brass block that the master lines connect to is a distribution block only, no proportioning there. When I replaced the master and booster with a 1995 XJ unit, I reused the original flare nuts on the distribution block and double flared the new supply lines from the new master because that's what I had on the original lines. Working fine, no leaks, for a few years now. Is this what you are asking?

[Eagle]

Double flare.

 

Bubble flares weren't being used by American cars at the time the MJs were being built.

[Akula69]

Ah - I'm sorry gentleman...I was using shorthand that only my brain could understand!

 

I was asking about the flares in general...I have replaced the power booster and the distribution block, but retained the prop valve in the rear and I am bending new lines for all of them.

 

We replaced the power booster Friday and had to replace the DS front line. Despite tightening all the lines we cannot get the pressure to build up. There are no leaks so all I can assume is air is being drawn in some where (however, once bled the system produces no bubbles!).

 

I was trying to determine what flares were used at the distribution block and the prop valve...but my brain was not translating it to my fingers doing the typing! :doh: However, I believe the answer is double flares all around.

 

Thanks!

[Akula69]

All installed - no leaks...but the brake light is still on.

 

It does have some stopping ability, but you have to be careful! I'll check for leaks again tomorrow and bleed it again I suppose.

[oldseddie]

I believe your problem lies in retaining the proportioning valve in the rear axle. It has a return line to the MC and there is provision for it on a Comanche MC. Did you replace the MC with a Comanche one?

[mvusse]

Sounds like air in the system, but it could be a faulty master cylinder. Could possibly also the above mentioned, but I don't think it is.

 

And our trucks use 45 degree double flairs.

[Akula69]

 

I believe your problem lies in retaining the proportioning valve in the rear axle. It has a return line to the MC and there is provision for it on a Comanche MC. Did you replace the MC with a Comanche one?

Yes, this vehicle retains it's proportioning valve. I am using a MJ specific distribution block which I have checked and cleaned.

 

Thanks

[Akula69]

Not the first time I've purchased a new 'defective in the box' item....I suppose I'll have to check it as well.

 

 

Sounds like air in the system, but it could be a faulty master cylinder. Could possibly also the above mentioned, but I don't think it is.

 

And our trucks use 45 degree double flairs.