1991 Reatta ABS

[Bushwack]

Regarding wheel speed sensors for the 1991 Reatta ABS, are they similar in design/construction (and where they are installed) to the 1990 MY? Do they have the same issues like most 1990 models where the insulation wears down due to road/driving conditions making the sensors faulty?

I'll be looking at a couple 1991 cars this weekend. While neither have brake issues, I was wondering should they in the future, are 1991 Reatta wheel speed sensors an issue like the 1988-1990 model years (and are they more readily available for '91s)?

[Barney Eaton]

1991 Reatta ABS seems to have less problems than the earlier Teves unit, but the wheel sensor design was the same technology.

Maybe it is purely a case of numbers, 1991 Reatta production was only 7% of total Reattas built, so you would expect fewer problems in total numbers.

Go to www.rockauto.com and look at the part number for 1991 ABS wheel sensors. It appears the same part number was used on all 4 wheels and the same part was used on Riviera, Toronado, Eldorado, and Seville with ABS. That alone help the possibility in finding parts.

Now look at 1992 Riviera with ABS on the Rock Auto site......it appears the hubs/bearings now have the sensor built into the unit. (and more expensive.)

I don't know if this answers your question or creats more.

[dship]

Front ABS wheel speed sensors are a separate part from the wheel hub for the 1991 Reatta/Riviera/Toronado/Eldorado. This was a one year only - 1991 - design. Rockauto's part number is ABS530069, GM factory part number is 3521274.

When you try to order these sensors from Rockauto, a message comes back that the parts are currently unavailable but you can leave your email address so they can contact you when/if any come in. All the other GM parts companies inform that the front sensors are no longer available (I've been looking for quite awhile!).

The rear sensors are built in and probably available but I've not inquired.

[Bushwack]

Barney: Thanks.

DShip: One of the cars I'll be looking at is a low mileage '91 Trofeo - thanks for the heads-up.

[KDirk]

Wait a minute. I thought the 91's (Bosch system) had integral ABS sensors in the hub assemblies (not separately serviceable) and the 88-90 (Teves system) had the removable barrel sensors. The way this thread reads thus far, the 91's are the problem parts, not the earlier Teves sensors which have been the source of much consternation here in the past. I am missing something?

KDirk

[dship]

Kevin...To your credit, you've not missed a thing (LOL)!

Although I've read many Teves threads on the forum, I am not personally familiar with previous years' ABS Teves Systems since I've never had a car that's had it.

I do know the 91 FRONT ABS speed sensors were a one-year-only-not-embedded-in-the-hub design as depicted in the 1986-1993 Reatta & Riviera Parts and Illustration Catalog. There's also a picture available on Rockauto.

The FRONT ABS speed sensors are embedded on my 92 Riviera.

[KDirk]

DShip,

so logically this leads me to ask if the 92 style front hubs could be used on a 91 Reatta (with their integral sensors). I know that ABS was optional on the Rivi until at least 90, not sure about 91-93. If the CV axles are the same on the 92 Rivi as the 91 Reatta and Rivi, and if the 92 front hub sensors have the same connector type as the 91 style, it may be worth trying. Was the ABS system on the 92 Riviera the same as the Bosch setup used in 91?

I know, a lot of questions, but now I am concerned about the ABS on my 91 as I had no idea (until now) that availability of sensors for this was an issue on the 1991 models.

KDirk

[padgett]

First, the 91 is not a Teves unit. At the same time the idea of a pulsed signal as a toothed wheel passes an electrical coil around a magnetic core (variable reluctance) is aunchient. It would not surprise me if sensors could be swapped. The important thing is that the different toothed wheels have the same number of teeth.

[dship]

Kevin,

92 front hubs on a 91...interesting....

First, what Padgett said.

Second, I've never considered it. I would think there's got to be some manipulation at the electrical connection point, though. Just looking at the 91 vs. the 92...

The 91 sensor is a bolt on at the hub with a long wire connection away from the hub. The 92 sensor is embedded in the hub with a short wire connection close to the hub. so, physically they are quite different.

[Guest Mc_Reatta]

What's surprising here is that 91 owners don't have a good grasp of their ABS systems. That goes a long way in documenting how much more reliable that system is compared to the rest of ours, even the wheel sensors.

As to using a 92 hub in a 91, as Padgett tried to point out, if the reluctor ring has a different number of teeth, then a 91, all 4 wheels would need the hubs changed not just the fronts. Probably only way to determine for sure is to replace one or two fronts and see if a ABS warning ensues. A modification to the connecting wire would need to be made to plug into the sensor at the hub, or a wire from a 92 would need to replace the one in the 91 and converted to plug into the harness under the hood. Certainly not an impossible task to keep the system active.

[wws944]

Looking at the illustrations pdf, the '91 Reatta uses the same front hubs and knuckles as the '89-'90. The '91 rear hubs and knuckles are the same as the '92-'93 Riv. So doesn't this infer that the tooth count is the same for all years? If so, it says that someone could easily swap '92-'93 front hubs/knuckles into an earlier car with impunity. As Mc_Reatta then says, some sort of wiring harness adapters would need to be made up to plug one style into the other.

These ABS sensors are annoying. Last year I had to replace one in my Suburban, and had to replace the whole hub as part of the assembly. And a couple of years ago, one of the front wires in my Rendezvous became intermittent. In that, the wiring plugs into the hub, so just a new wire had to be spliced in. Now the other side is starting to go...

[DAVES89]

I am so paranoid about the Teves ABS leads that I now have 12 front/12 rear in back stock with another 2 front/2 rear on order from a yard I deal with. On the Red and Black I had to replace all four on each about 3 years ago. Just want to be ready...

[Guest Mc_Reatta]

I am so paranoid about the Teves ABS leads that I now have 12 front/12 rear in back stock with another 2 front/2 rear on order from a yard I deal with. On the Red and Black I had to replace all four on each about 3 years ago. Just want to be ready...

I'll be looking for you to show up on that TV show "Hoarding, Buried Alive" soon!

I'm still looking for a decent source for the weakest link in the sensors, the cable. Last one I found that looked interesting and affordable was only rated ultraflex to -4 deg C. Would only work on southern or summer only cars. May have to go with it if I can't find something else better.

[Bushwack]

This is a bit off topic but as I stated in my original post, I was looking at two 1991 cars. One happened to be a 1991 Olds Trofeo...but as it turns out, it's a 1992.

I couldn't (actually didn't want to) drive the car. It's flawless inside and out and starts up (even the original CRT works) but my main concern and possibly largest expense outside of new tires is determining why the brake light stays on. Story behind the car is the owner bought it new for his wife, who passed away two years later. He kept the car (among others he owns) but he hasn't driven at all since 1995 (when he had a stroke). Since then, he's hired students throughout the years to turn over each of his cars on a monthly basis. He's also had a couple local high schools and trade schools come and change out fluids as part of their shop class. Anyway, the Trofeo is a low mileage moment in time but hasn't really seen sunshine in many years and as I said, the brake light stays on.

From the posts I read earlier, I've concluded (long ago) that anything can be repaired. I will most likely buy the Trofeo and let my mechanic figure it out.

[DAVES89]

Sorry for my prior post. Typed without thinking. I have a total of 12 6 front and 6 rear with 2 make that 3 front and 2 rear coming.

There is a Teves Bonneville in my local U Pick that just came in. It has the wrong fronts which means that they are [what would be for us Reata owners] all rear sensor leads. I can almost certainly say that they will not come willingly out of the hub complete. They will leave the outer aluminum barrel behind. I have swapped the leads [w/o the barrel, guts only] into the Black with excellent results. The Black [being my winter driver also has rusted in barrels] so I just swap in the guts and caulk off with silicone sealer. Now completed two winters and everything still works.

[KDirk]

Given what Walt has posted upthread, I think the 92/93 Rivi hubs can probably subbed in electrically, the need to add/modify a section of harness notwithstanding. The next question is whether they will fit on the outer end of the CV axles as-is. I cannot imagine GM would have changed the whole setup again after just one year (91). Rather, it looks to me like the 91 hub design was re-used from the Teves system with different sensors fitted. In fact, the sensors are likely the same, but the connector on the end of the harness is going to be different.

The sensor lead connector used on the 88-90 Teves sensor leads is a very unusual round weather-tight connector sourced from AMP GmbH (German arm of the electronics firm AMP). Since this is what Teves spec'd on the sensor leads, GM used them as-is (the sensor leads were likely not made by GM, but were sourced from Teves and used on GM cars with ABS systems). Since GM usually used sensors of their own design (Weatherpack in most applications subject to moisture intrusion) when they switched to Bosch ABS systems in 91 the connectors were changed to standardized GM parts. The upshot of all this is I bet the 91 sensors are just Teves type with weatherpack connectors fitted instead of the non-standard AMP type of the previous three years.

This appears to have been a transitional design in 91. What is more interesting (based on Walt's post) is that the rears were already changed to integral sensor-in-hub types (just as all four wheels on my 95 Deville are) in 91, which tells me GM had been engineering new sensor and hub assemblies for the changeover to Bosch, and probably didn't have the new design for the fronts ready in time for production. Thus, 91 got the new design hub/sensor assemblies in back only, and the revised design was rolled out on the fronts in 92. Would be interesting to know if any ABS equipped GM cars in 91 got the new design in front as a running change.

I need to look in my parts manual now and see if the ABS controller module (EBCM) is the same in 91 and 92. If it is, then there is certainly no reason there should be an electrical incompatibility between the 91 and 92 front sensors. If they are different parts, then 91 may have tweaked firmware to account for differences in the input signals from the front vs. rear sensors.

If anyone has an old 91 front hub in a parts box and could count the number of teeth on the ring, then we just need to find a 92 to compare it to for the same number of teeth, and for identical mechanical fitment.

Time to do some research.

KDirk

[Guest Mc_Reatta]

Some preliminary research on 91 vs 92 hubs doesn't look too promising. 92 Riviera axles are not the same as 91s. Looks like 92s had 33 splines while 91s had 27. If that count is true on the outer hub end, then 92 hubs can't be used on a 91 Reatta or Riv even if the ABS sensors could be made to work.

Would be nice if someone having access to 91 and 92 parts could verify that the diam. and or spline count on the outer axle ends or hubs are indeed different.

Would have been real sweet if we 89 to 91 Reatta owners could have installed 92 Riv hubs and just modded the wires to get the ABS sensors to play.

[KDirk]

Of course. Every time something should be simple, I end up getting screwed by some stupid detail. You just know there was no good reason to change the outer spline from 91 to 92, heck the Riviera was virtually unchanged for 91-93 and yet GM just had to go and re-engineer the CV shafts on a car that was otherwise the same as the previous model year: same engine, same transmission, same electronics. Almost like they did it purposely to make sure no one could substitute a new part. As much as GM is criticized (and rightfully so) for bean counters insisting on the reuse of existing parts for many years running (gotta get every last red cent worth out of the R&D and tooling you know), there seems have been a lot of completely un-needed re-design of parts like this that occurred in the early to mid 90's.

So, I suppose the next question is whether the inner spline on the 91 CV axles is the same as 92 & 93, or if they changed the spline socket on the transmission as well (and that would be the final insult). I would still be ok with having to change CV axles to use the new hubs, since my 91 has the original front hubs yet, and at 108,000 miles they will be due for replacement sometime soon. If the shafts can be changed, and the 92-93 hubs are electrically compatible (which it seems they should be based on preliminary findings) then it is a more expensive mod. However, if you need new CV axles anyway, it isn't such a bad deal IMO - assuming it can be made to work on the transmission (inboard) end of the shaft.

I haven't had a chance to dig out my 86-92 E platform parts manual yet, but I hope it will offer some clarification on this. Also, I should point out that I do not presently have any ABS problems with my 91, but I like to plan ahead, especially when parts are not available and substitutions need to be considered. If we can come up with something that works here, it not only helps me when the time comes, but anyone else who needs to deal with bad ABS sensors on an 91.

KDirk

[DAVES89]

I just got back from Gibson's and because they have to be compliant with the DNR regarding drainage and ground cover they constantly move and crush our vintage [Rivs/Reattas] cars. Right now there are no 91's or later Rivs for me to look at. Sorry...

[KDirk]

Dave,

I will probably go irritate the counter guy at my preferred parts house into letting me inspect hubs and shafts for both years so I can visually compare them. If the 1991 shafts can be changed to the 1992 type, and 92 hubs installed, then that is the answer. There will be the added issue of wiring harness modifications, but that is of no concern to me. This assumes the hubs bolt up the same, and that they will output the same signal as expected by the 91 computer. Yes, all of that is a lot to assume so I am not expecting good news. Without at least looking at the parts, there is definitely no way to know, so that will be my next step.

Sorry to hear that Gibson's has cleared the yard of usable E platform cars. I don't know how often they get Reattas Rivis and Toros of that era in there, but when I was up there visiting, most of the 80's/early 90's E bodies were already kind of picked over. You and I probably took most of the remaining good stuff at the time.

KDirk

[Guest Mc_Reatta]

I know the inner spline was changed in 91 so there's no hope for us 89, 90 owners to move up to 92 axles without tranny and ECM upgrades too.

I'll keep my fingers crossed for you 91 guys. Right now I'd guess there's a much better chance of 92 hubs working electrically vs mechanically.

One very slim hope left alive is if a CV joint re-builder could graft a 92 outer spline into the outer (or axle to an inner for that matter) CV joint on a 89-90 or 91 axle or inner spline. Any CV joint workers out there? Took one apart once but without proper knowledge and tools it wasn't pretty. That would yield a hybrid axle, 89-90 or 91 on inner end, 92 on outer.

[KDirk]

MC-

What you have just proposed also occurred to me, but makes the process even more difficult and expensive. May be the only remaining option though, if none of the other ideas here pan out. I'm not sure a re-builder would do this, citing the possibility of the mixing of axle parts as inviting failure of a safety critical part (CV axle malfunction begets possible loss of control of vehicle which begets crash=lawsuit). Since it is not exactly a DIY project (though if correct tools and parts could be had by us mere mortals it could be done) we would probably be stuck trying to get a re-builder to produce such a Frankensteinien axle. This also necessarily requires that the 92 outer axle/joint is mechanically compatible with the inboard side of the 89-90 or 91 axle.

If the morons in engineering changed the number of splines, they may well have also made dimensional or other changes that negate the possibility of building such a rigged-up axle assembly. I am really getting sick of so many things being so difficult when they should be straight-forward; a problem that goes well beyond just working on my cars. This episode is just another example of abject idiots smegging things up for the sole purpose of irritating me. My thanks goes to the "great thinkers" at GM circa 1991-92 for this one. Nice going guys.

KDirk

[KDirk]

Ok,

Did some research and discovered some further details. First, according the computer at the parts store I frequent, the 91 and 92 Riviera CV axles have 35 splines on the inboard (transmission) end, 33 on the outboard end. It also shows the 91 Reatta with 33 splines (not 27) outboard, 35 inboard so now the spline count is in doubt again; this may be an error in the computer listing however. I will need to see one of each to physically verify the outboard spline count.

Other issue is that the driver (left) side CV axle on a 91 Reatta has an overall length of 20 15/16" (per the computer listing) where the 91 and 92 Rivi left side axle has a listed overall length of 21 1/2". I'd have thought both cars used the same axles, given their similarity in most everything but the body. So, substituting a Riviera axle on a Reatta is clearly not workable due to a difference in length. That said, there is still the slimmest of chances that the hubs can be interchanged if they are all 33 splines on the outboard end.

What I need now is to find a 91 hub (even a junked one removed for replacement) to compare side by side to a 92 Riviera hub (the store stocks these) so if anyone has an old hub removed from a 91 Reatta lying about, please PM me. Also need to talk to a local outfit that does axle rebuilding, to see if they can confirm the spline counts by model and year for me.

KDirk

[wws944]

...Other issue is that the driver (left) side CV axle on a 91 Reatta has an overall length of 20 15/16" (per the computer listing) where the 91 and 92 Rivi left side axle has a listed overall length of 21 1/2". I'd have thought both cars used the same axles, given their similarity in most everything but the body...

According to the illustrations pdf (page 6-17) there isn't any difference between Reatta and Riv axles in '91. Part nos in '92 and '93 are definitely different though. And it looks like there was a running change in '92 on the LH side to the '93 part.

[DAVES89]

Here is more info on the 1991 abs sensors...