bazz54 Posted August 4, 2023 Report Share Posted August 4, 2023 (edited) In the Gen7 sub-forum, I've been talking about some quirkiness with my ABS. I have now have the sensor out. It seems that they are installed with a metal shim beneath them to set the clearance and this has rusted to pieces - see pics. The first pic is the sensor after wiping away the muck with my finger and the second as it was when removed, with the pole covered in rust . However, there was clearly a shim under the sensor which has completely rusted away. This Youtube shows a man fitting shims under a sensor https://www.youtube.com/watch?v=5UDpWyIvWC4 Do we know anything about what Mr Toyota does on Celicas? No mention at all of this in the Toyota workshop manual. I'm told the manual should give a shim thickness, typically 0.6 to 0.9mm. My car is 21 this year, so it's potentially a problem arriving with any Gen7 sometime soon. Edited August 4, 2023 by bazz54 Link to comment Share on other sites More sharing options...
Bumblebee Posted August 4, 2023 Report Share Posted August 4, 2023 Maybe it's my eyesight but I can't ever remember seeing a shim under the sensor and I've had a few out over the years Link to comment Share on other sites More sharing options...
bazz54 Posted August 5, 2023 Author Report Share Posted August 5, 2023 This is the very first time I've ever got involved with ABS sensors. There's the YouTube video above where a guy was clearly installing new shims with a new sensor. But, I found a video of a guy replacing a sensor on a Corolla and there were no shims. Conversations I've had elsewhere confirm some cars/bikes have them and the manual would specify the thickness. The shim sets the clearance between the sensor pole and the reluctor ring. I think you can see at least part of the shim on the second picture above; it had completely changed to rust, some of it just fell off, some of it was well stuck on. In terms of the Gen7, could it be that some production batches had them and some not? It's not that unusual for there to be some variations over the production run of a car's lifetime. My 7 is a pre-face from 2002. Ideally, I could contact Toyota and they would tell me, but I suspect that support for the Celica is pretty minimal and this is very obscure. I am only the second owner of the car, which was only 3 years old when I got it. Given that there was a shim on mine, I think I have to re-assembly it with something equivalent; I've made one out of aluminium just to keep me on the road (have yet to install and test it). Link to comment Share on other sites More sharing options...
bazz54 Posted August 5, 2023 Author Report Share Posted August 5, 2023 (edited) Inserting the sensor as far as it will go in to the hub (presumably the point at which the sensor is touching the ring) then there is a gap of ~1.5mm between the underside of the sensor shoulder and the hub. So to give a clearance to the ring of say 0.5mm, the 'shim' would need to be 2mm thick. Edited August 5, 2023 by bazz54 Link to comment Share on other sites More sharing options...
Xanadu Posted August 5, 2023 Report Share Posted August 5, 2023 4 hours ago, bazz54 said: Given that there was a shim on mine... Is it possible that the 'shim' was just a thick layer of rust that detached itself from the surface of the hub casting? Link to comment Share on other sites More sharing options...
bazz54 Posted August 5, 2023 Author Report Share Posted August 5, 2023 What was it that Sherlock Holmes said about ruling the possible things out? I hadn't thought of it but you'd have to think it's possible that something odd with the casting happened. I've just found out that the part number on the sensor is the right Toyota part. One thing's for sure; that sensor and that hub cannot be used together without some "restorative" addition. I never intended to take the sensor out at this stage, but noticed that the 10mm hex head mounting screws were very rusty and thought I'd try change them before they got worse. The sensor just came out with the screw. The road to hell... good intentions . Link to comment Share on other sites More sharing options...
Bumblebee Posted August 5, 2023 Report Share Posted August 5, 2023 You can easily check the clearance Piece of kids playdoh or something like it placed in the hole, fit the sensor, remove sensor and playdoh and measure thickness. No guessing then Link to comment Share on other sites More sharing options...
armoredfist2002 Posted August 5, 2023 Report Share Posted August 5, 2023 No shims on the gen 7, it's the rust off the housing, I didn't have any on mine when I did my refurb over the last 18 months. If you've got rust attaching itself to the sensor as they are slightly magnetic then that could be the cause of your ABS issue like in the first 2 pics. Link to comment Share on other sites More sharing options...
bazz54 Posted August 5, 2023 Author Report Share Posted August 5, 2023 Thanks for the comments. No Playdoh, but got some Bluetack. 1 Link to comment Share on other sites More sharing options...
bazz54 Posted August 7, 2023 Author Report Share Posted August 7, 2023 (edited) All problems solved... I think. The outcome is a surprise, but makes everything understandable, which is good. The issue lies with the precise shape of the sensor; it has a shoulder on the section that goes in to the hub and I had not noticed that the shoulder has a slight taper and so it sits in the hub a bit like a cork in a bottle. The "shim" was 21 years of rust and muck. I've tried to do a reasonable drawing as attached. Put it back with no shim (it's a long story getting to that point) and all is good and the ABS rumbling at low speed appears to be gone. Changed the oil and filter while I had it on stands. Many thanks for you contributions - always good to be able to bounce ideas off people when you're struggling gen7 abs sensor.pdf Edited August 7, 2023 by bazz54 2 Link to comment Share on other sites More sharing options...
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