D35->D44 swap: rear brakes proportioning?

[mhead]

Hi All,

I swapped in a D44 for my D35 in back in my '92 XJ I-6 auto. It had ABS but I simply unplugged the pump unit and left the hydraulic plumbing alone. The new D44 does not have sensors at the wheels so I can't use it.

The new D44 has much larger brake drums and wider shoes than did the D35. I'm expecting that this will give additional braking power above what the D35 had.

When I stomp on the brakes I can slide the rear (D44) wheels a lot sooner (at lower pedal pressure) than the front ones slide. Of course the XJ is light in the back and tends to rock forward when stopping so some of this is expected. But it seems that the back slides more easily than I would expect.

So my question is: Is there a valve or something that regulates the ratio of hydraulic pressure to the front and back? If so is it adjustable? Anyone know how to measure what this valve puts out or a specification of what it should be doing for D35 vs D44?

Thanks!

[massxj]

you are using half a brake system and think its going to work normal? i would start by getting a prop valve from a non abs xj remove all the abs stuff and see what happens from there

[Eagle]

The combination valve on the XJ serves both to trigger the brake warning light and as the proportioning valve. On non-ABS XJs this is located immediately below the brake master cylinder. I've never worked on an ABS-equipped XJ of your vintage, so I don't know what the ABS system used. Given how ABS functions, I sort of doubt that it has any proportioning valve. Why would it need one if the ABS won't allow a wheel to lock?

You could replace everything with stock non-ABS parts, or you could go to Summit Racing and buy a Wilwood adjustable proportioning valve and just plumb that into your rear brake circuit. The stock proportioning valves go bad, so I'd look seriously at the Wilwood.

[Red97XJ]

Wilwood. Super sweet, totally adjustable.

My first one was on my 427 S/C Factory Five Racing COBRA.

very nice to adjust WAY better than stock.

Jason

[Beezil]

Wilwood. Super sweet, totally adjustable.

My first one was on my 427 S/C Factory Five Racing COBRA.

very nice to adjust WAY better than stock.

Jason

important:

2lb ers for discs

10lb ers for drums

[Joe]

Hi All,

It had ABS but I simply unplugged the pump unit and left the hydraulic plumbing alone.

My question is why did you have to disconnect the pump?

When I did my swap I just cut the sensor line and the system is working great. Of course I no longer have ABS brakes eventhough the whole system is still intact. I have a 94 and if I am not mistaken the 92 should be the same. Can someone correct me if I am wrong.

[XJ_ranger]

My question is why did you have to disconnect the pump?

When I did my swap I just cut the sensor line and the system is working great. Of course I no longer have ABS brakes eventhough the whole system is still intact. I have a 94 and if I am not mistaken the 92 should be the same. Can someone correct me if I am wrong.
interested in knowing this as well - looking into a D44 / C8.25 rear end and ditching the ABS...

[mhead]

My ABS problems go way back. Hunt on this site under mhead and you'll see other posts. Basically the ABS came on randomly and locked the brakes for me at unexpected times. I never did figure out why, but the problem disappeared after I unplugged the ABS pump.

So when I swapped the D44 in I had already disconnected the pump.

Jeep operated normally with the D35 and ABS unplugged. I didn't notice any braking problems.

I'll probably follow suggestions on this thread and buy and insntall the after-market proportioning valve. Guess I should rip out the ABS pump and plumbing at the same time. This will give me a little more room in the engine compartment.

Thanks for suggestions above!