ERA Vs Jag Rear End

[iwantacobra427]

Obviously you can change the ERA rear end brake pads a lot easier than the Jag and weighs 50 lbs less... other than that what other benefits are there? How difficult is it to service both differentials? Do you have to drop the Jag rear end to change the brake pads? How about bleeding the Jag rear brakes? My FIA will be for street use.. Thanks for your input..

[LMH]

This is too strange...I was wondering the same thing yesterday. So I'm really glad you posted this question as I'd like to know thoughts on the two rear ends also.
Larry

[decooney]

FYI: As for the Jag rear setup, between the two seats on my 427/ERA there is an aluminum inspection cover that can be removed. You can access the Jag rear brakes, pads, lines from there.

To service the rear end internals, you basically remove the entire subframe with two upper bolts, two forward control arm/bolts, driveline bolts, brake line disconnect, and the entire unit can be dropped out for major servicing. A nice little floor jack/scissor jack and cradle makes it easier.

[chuckbrandt]

When people ask my opinion I recommend the ERA suspension which is what I have on my car. A couple of years ago there was an issue with the Jag suspension having a lot of wheel hop on accelleration. It was so bad that on my friends car #664 it would shake the passenger door open. I haven't seen any of it on my car. Someone was engineering a bolt on fix to the problem but I haven't heard anything about it in quite a while.

I'm afraid I know very little about it beyond that, maybe some of the people involved can chime in and set me straight. There are certainly other differences between my car and charlie's that would contribute as well, he has 17" rubber vs my 15", different shocks etc.

Just wanted to raise the issue.

Chuck

[Jim Holden]

iwanta:

Aside from the outboard brakes, the ERA rear adds a fourth link that helps control the movement of the hub. According to those ERA owners who have tracked their cars and have experience with both rears, a car with the ERA rear corners a little "flatter". Too, the outboard brakes are easier to provide ductwork for cooling even though there may be a minor increase in unsprung weight. However, unless you are a serious open track type guy or are (in my opinion) an abuser of clutches with wheel spinning starts etc. the Jag rear is more than adequate and provides an excellent ride.

I've had both rears and have never experienced any wheelhop with either system.

Jim

[chuckbrandt]

Thanks Jim,
Your first hand experience is certainly more valid than my second hand rumors. I only brought it up because I assumed the earlier threads on the subject got lost over the years. I just did a search and they are still there including the ones about the kit with the horizontal shock thing.

Above all, I Iwanta should get a variety of opinions on it and weigh his intended use of the car.

Chuck

[Excaliber]

Man bleeding the brakes on the Jag rear from UNDER the car is all but impossible! Removing the seats and the 'access' panel makes changing the pads and bleeding very easy. But it's a pain having to remove the seats to bleed the freakin' brakes!

My Jag rear has been modified with a kind of 'torque' control arm to stop the axle hop. VERY effective, it just squats and goes with no hop at all.

If I was ordering new I would CERTAINLY go with the ERA rear end, love those out board brakes and lighter weight, but the old Jag style 'aint that bad'.

[decooney]

Originally Posted by chuckbrandt

Someone was engineering a bolt on fix to the problem but I haven't heard anything about it in quite a while. Chuck

Chuck,
I did, and it works. Part of the issue starts with tires/roundness, tire pressure, length and alignment of the cradle subframe. To help cure the remaining hop I had, from there I engineered a fore/aft dampner configuration that bolts directly to the Jag hub on an ERA and ties into the frame mounts next to the fuel tank. I have it installed, CJ428CJ here in CC, and a few others not on this site have it. The dampner travels 1/4". So far so good.

[Chaplin]

FWIW, I have the standard jag rear and have absolutely no problems with wheel hop whatsoever and the inboard brakes are fine for the everyday driving. However, with that being said, if I were to do it again, I would go with the ERA rear simply for ease of maintenance on the brakes, taking out the seats to change pads/bleed is a PITA. Plus, the ERA rear looks so damn purty too!

[CHANMADD]

I fabricated rearward radius arms for my jag rear end and it has behaved perfectly for the last 14 years.I chose rearward because I could make them longer thus reducing the amount of toe effect when the wheel moves through its arc of travel.the jag rear end is super strong when installed properly,also you should try to get factory controil arms and driveshafts from an old S type or MK10 they are the correct length and require no welding etc

[iwantacobra427]

Ok I'm going with the ERA based rear end... Removing the seat and a hatch to service the brakes doesn't sound very appealing

[Excaliber]

Hey it's not 'that bad' I got to where I could snatch those seats out in no time (just put 'em back in with only two of the four bolts)!

[Goopie 18]

I was the owner of a 67 E Type for several years. Wait until the rear seal leaks and drips on the rear pads. Jag rear was nothing but trouble. It's one of the reasons why I've ordered a SPF.

[decooney]

Hmmm. I'm ceratinly not waiting for that to happen, and backed with an opposite story to tell. After building, owning, driving and servicing two Cobras with Jag rears in them that I built myself, never experienced that problem. I can change my pads on my ERA in 15 minutes without removing any seats. A friend in the club had 45,000 miles on his ERA with a Jag rear, and not a lick of problems with that either. He drove that ERA across the country and back twice, owned it and drove it for over 16 years solid. Then he sold it and missed it so bad, he went right out and purchased another ERA, used, with a Jag rear in it. Still, no major brake or leaking problems. Interesting, I guess it's possible that only some of us have all the luck.

[Chaplin]

Originally Posted by decooney

I can change my pads on my ERA in 15 minutes without removing any seats.

'splain please! Did you create a trap door in the rear bulkhead to allow quick access to the brakes?

[decooney]

Chap,
No, if you are talking about brake pads only - I just slide the seats forward on the tracks (if you have tracks), remove the inspection panel, and there they are. Another way I've done it on another car, is from underneath, not as easy, by reaching up in there and feeling around. The first time takes a bit longer, but after you've done it, gets easier. Worst case, if you can't get to them you could remove the large bolts and drop the subframe down I guess. Good luck.

[Excaliber]

I considered some kind of 'piping' extension on the brake bleeder valves for easier access to bleed at the track. For normal street use you don't have to bleed the brakes so often, so not as big a deal. Rear brake pads were a pain to replace in the Jaguars as well, but it could be done (and there was NO access hole to do it)!

I would take a Jag rear end over a Ford IRS unit used in the SPF any time! It's not like the SPF rear's are 'perfect' and 'never' break! I would guess MORE people have trouble with them than the Jag setup. Just try buying a CV joint for one, I double dog dare ya!

[luke-44]

You may check with Peter or Doug at ERA - I think they'll tell you changing the pads is like a once or twice in a lifetime thing - the car just doesn't use up rear pads.

[RACER X #99]

Since I have a Jag rear in my Contemporary and only use the car for open tracking I know a little about changing pads and bleeding brakes.I use two sets of rear pads a season so using the Jag setup sucked. I changed to the Wilwood Dynalite calipers with slotted rotors. I also installed a cooling fan in the trunk that blows fresh air to both rear calipers. The inboard brakes are noted for getting real hot when in track use.
I have radius rods that run to the front and attach to the frame about midpoint between the front and rear wheels. The alows for zero tow change under hard acceleration and also zero change thru full swing of the suspension.
I have also plumbed my rear calipers both inner and outer with brake lines extending to the rear frame so I can bleed the rear brakes without even having to jack the car.

This kind of stuff is probably not necessary for street driving but to me street driving is boring.

RD

[RICK LAKE]

I have inboard rear brakes and rebuilt the carrier myself. Except for the spacers for the correct hub play, have had no problem racing. If you have oil leaken out a seal on the brakes, there is a problem either in the vent tube and too much pressure is building up and pushing fluid out or the stub shaft axle is wobbling. Depending on what carrier is in the case,you really don't need to change the oil more than once at 50k miles. synthetic oils work very well in the rear end. As for bleeding the brakes, I can manually do it in 10 minutes my self with the ERA panel removed. I am sure it will can a little longer with the interior rugs in the car. There are kits for ducting outside air to the brakes both front and rear. As for the wheel hop, This depends on how high the rpm is before the clutch is dumped,type of tire amd how many heat cycles in them. I race at Run and Gun, leave the line at 1600 rpm with a set of 335x17" pilots on the rear, it squats 2" and leaves, no tire spinning or hopping. Suspension is the big thing and if not set up correctly, the car is going to handle poorly. Wieght balance the car with you in it, get the alignment setup to the Spec in the ERA manual, It is tough finding a shop to setup the Jag rear to spec with the shims going in the drive shaft points and the toe being shimed on the lower connection points. This process takes 2-4 hours with all the adjustments. Front and rear. You then need to safety wire some of the bolts back up. Rick Lake