So we just took our car to the dealership for service. The told us that the brake pedal is soft due to missing brake shims, and it's a safety concern.

We had our brakes done at an independent garage about 2 1/2 years ago, with OEM pars I bought at Lexus parts World. I only bought pads and rotors, so it's possible they didn't install any shims. But from what I read online now, brake shims are not necessary for proper functioning of brakes, they are more a feature to cut down noise and even out the pad wear.

So is the dealership right saying missing shims is a safety issue? The brakes in our RX350 are pretty soft, but they have always been like this (compared to my BMW at least) and I have not noticed them being noticeably better or worse after the brake job. From what I gathered reading here, soft brakes seems to be a design flaw with that generation of RX (and some other Lexus cars from that area).

 

Missing shims should not produce a soft pedal feel. You could even make an argument that it should make the pedal firmer. Having no spacer between the caliper piston and the pad itself. Not saying that is the case, just that it makes no sense that a missing shim would make the pedal feel soft.

 

I agree the missing shims are not a safety issue. I also agree the RX has a soft brake pedal and there is not much that can be done about it.
Your new pads may have had shims built in and may look different enough from OEM pads that the Lexus dealer is not familiar with them. I would get a second opinion from an independent shop who will be less biased to make their sales commission quota for the month. How much wear is on these brake pads? Usually bleeding the brakes and cleaning and lubing the brake caliper slide pins will help with brake pedal feel.

 

I humbly disagree and would side with the dealership. The shims not only provide clearance (rattle/noise/boot-to-pad_clearnce, heat dissipation) they also hold/guide the movement of the pads.

So would I stop driving and flat bed the vehicle ,,,, No, but I would put back the shims at earliest time. IMHO the safety issues are more long term and not immediate. 2 1/2 yr is getting long term. There are flat sheets behind the pads and holding clips.

Soft/hard is subjective to begin with as the ease of effort is involved. The quantifiable terms are ... does the brake pedal stop moving at the specified distance [rule of thumb ... your left toe can easily go under the pedal at max travel]. Does the vehicle stop in specified distance from a specified speed [part of safety inspection] and then there are other issues like dragging and abnormal wear.

Salim

[I am only familiar with OEM stuff]

 

Shims slightly soften the pedal. There is absolutely no way a lack of shims is a safety issue, never go back to that dealer.

 

I have to agree. I just went and looked at both my SC and RX and in both cases the shims do not have anything to do with positioning of the pad. No way is it a safety issue. Many years ago we used pads that had no shim at all.

 

Thanks for the responses guys. Doesn’t sound like it’s a safety issue. also don’t think the brake pedal is dangerously soft honestly, like I said it’s been like that from day one. After we got the brakes pad and rotors done, brakes felt better for a few months, but then kinda returned to their previous feel. I hope Lexus fixed that on newer vehicles.