Hi All,
I'm a newbie who just recently purchased a 1600cc 2 door ford escort with a 2L pinto put in it.
The car isn't in great condition and there is plenty of love needed.
At the moment:
NO rear drum brake assembly
NO rear shock absorbers
I was told the diff needed some attention (which means it will be thrashed)
I'm setting this car up eventually for rally but trying to make it road legal.
I want the car to have full brake and suspension upgrade.
My question is should I replace the diff entirely with disc brakes. Or is it simpler to purchase the r31 brakes mounts and then adapt them to the original diff? I've seen that you need to do plenty of work on the original diff for the discs to fit. I've looked around but haven't much luck!
Any suggestions? Thanks! 

Firstly where abouts are you?
Secondly whats your budget?
 
If your diff is really thrashed i'd source another complete escort diff, there are plenty of decent ones around if you look. Discs are nice but i don't think overly necessary, as long as your drums are working well and serviced regularly they can work just fine for most cars.

But if you are set on discs in my opinion its much easier and cheaper to go the R31 route than get another diff which comes with discs. Because all other diffs with discs you are going to have to shorten it, and also change the stud pattern anyway. Both cost money, particularly the shortening - BIG money. But if your looking for a super strong diff this is sometimes the better option. 
For rally most use a hydraulic handbrake which isnt legal on road (unless you have both a standard cable handbrake for parking, and a separate hydraulic handbrake).
I myself have gone the R31 route in my project car. I have a spare Hilux diff there if i ever get fed up with it, but ill see how the standard diff goes first. 

Here is a link to a thread that i started. http://www.classic-ford.org/cfp/tm.aspx?m=45153
 
May answer some of your questions
 
Cheers and welcome,
 
Matt

Thanks guys I really appreciate it! I live in Adelaide.
Honestly budget wise. I'm not particularly worried but I don't want to be spending thousands if I can do the r31 route with the diff I have for 3-4 hundred.
I bought the car of a bloke for a very good price but when he said something needed 'looking at' It usually mean that it needed replacing 
I will take the diff apart and see the condition of it this weekend.
I was interested in doing the r31 conversion but I could not find much information on the setup of this. Especially since there was talk about milling the axle flange and such.

Hi Matt
Unsure if you have contacted me previously but feel free to PM your number and i can call regarding the R31 kit etc.
Personally I think the standard Mk2 diff is fine for the street if treated with some respect. If it breaks and you're sick of it then upgrade to another option etc as the outlay to put discs on it is minimal in comparison to altering a donor housing, shafts etc.
 

Hi Paul, we have had a quick chat a few weeks ago. The issue is the car will not only be driven on the street, the plan is to have the escort as a track day car but try and maintain some sort of roadworthiness. The issue is I don't want to spend time and money building up the original diff when I know the diff is going to have a hard life. If they are strong enough for rally situations then I'm happy to use the original diff but most people suggest that the original diffs are pretty poor.

You can always throw in a standard diff and see how you go and then upgrade to an  LSD if you need to down  the track.
 
Importantly is how much power you expect to put through it.  Anything more than 150 - 160 odd horsepower and you need to think about a diff but it also depends on driving style too.
 
Plently of guys rallying with standard diffs although yuo may want to weld it up.
 
Cheers
 
Matt

Yeah ill probably end up going down that path. It's a standard pinto so hp limit won't be an issue

I had a standard diff in a 180hp Pinto Mk1. It was fine, but i didnt beat the hell out of it.
Id keep the original, see how it goes but be looking around for a tougher option just incase it does go (either hilux or shortened BW) .

Thanks guys, I will be keeping the original diff in place. My biggest goal is to make sure it still stays road legal. When you put the rear brakes on, does the brake bias go wildly out of whack? and if so what method of adjustment do you use? I'm still in the market for suspension as well. Any threads or recommendations?