# Brake System Pressure Adjustment in Upland > Rear brakes locking early or a truck that stops poorly when loaded? We check brake pressure balance and adjustable load valves in Upland. Source: https://route66autorepairshop.com/brake-services/brake-system-pressure-adjustment Updated: 2026-09-17 Business: Route 66 Auto Repair, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699 Hours: Monday to Friday 8 AM–5 PM, Saturday 8 AM–2 PM, Sunday closed **TLDR:** Front-to-rear **brake balance** matters most on trucks that haul. We check the **load-sensing valve** where fitted and tell you when your car has no adjustment. Brake system pressure adjustment sets how much braking force goes to the rear wheels compared to the front. Route 66 Auto Repair in Upland checks this balance on trucks and older vehicles with an adjustable load-sensing valve, and on vehicles that stop poorly after a lift, a spring change or a heavy load. Many newer cars manage balance electronically and have no adjustment at all. We tell you honestly which kind you have before quoting anything. ## What are the signs of poor brake balance? - Rear wheels lock or chirp on an empty pickup during a firm stop - The nose dives hard and rear brakes seem to do little when loaded - Rear pads or shoes barely wear while fronts wear quickly - Braking changed after a lift kit, leveling kit or new springs - The rear feels loose on downhill stops ## Does your vehicle have an adjustable valve? Some pickups, vans and older vehicles use a load-sensing proportioning valve mounted near the rear axle with a linkage to the suspension. As the rear squats under load, the valve lets more pressure reach the rear brakes. If the ride height changes, the linkage needs resetting to the maker's spec. Most modern cars use electronic brake force distribution through the ABS unit, so there is no valve to turn. On those, a balance problem means a fault somewhere else, and we move to [ABS system diagnostics](https://route66autorepairshop.com/brake-services/abs-system-diagnostics) or a valve check with [brake proportioning valve repair](https://route66autorepairshop.com/brake-services/brake-proportioning-valve-repair). ## Our pressure adjustment process 1. **Identify the system:** We confirm whether your vehicle uses an adjustable valve or electronic distribution. 2. **Check ride height:** Rear height is measured, and any lift or spring change is noted. 3. **Measure pressure:** Gauges show front and rear pressure so we see the actual balance. 4. **Set and verify:** Where adjustable, the linkage is set to spec, then we road-test empty and, if possible, loaded. ## What's included - System type identification - Ride height and linkage inspection - Front and rear pressure readings - Valve linkage adjustment where the vehicle allows it - Rear brake wear check - Road test and written findings ## Need-now or need-later? **Need now:** - Rear wheels locking under normal stops - A seized or disconnected valve linkage **Need later:** - Uneven front and rear pad wear with no handling change - Planning a suspension change and wanting the brakes checked afterward ## How pricing and timing work Diagnosis comes first. The diagnostic fee is stated at the counter before testing and applies to approved related repair. A linkage adjustment is usually modest. A seized valve or ABS fault costs more and is quoted in writing. Fleet trucks get unit numbers on invoices. AAA members get 10% off parts and labor, up to $75. We give a time window the board can hold. ## Aftercare If you change ride height again or add a regular heavy load, have the balance rechecked. Trailer brakes are a separate system; see our [towing and U-Haul page](https://route66autorepairshop.com/u-haul-rentals) for the hookup check. ## Frequently asked questions ### Can you turn up the rear brakes on my car? Only if it has an adjustable valve. Most modern cars control balance electronically, and there is nothing to turn. On those, we look for the fault that is causing the imbalance instead. ### My truck brakes changed after a lift. Why? A lift changes the angle of the load-sensing valve linkage. The valve may think the truck is heavily loaded all the time, or lightly loaded. Resetting the linkage to spec usually restores the balance. ### Is poor brake balance dangerous? It can be. Rear wheels that lock first can make the vehicle swing sideways, especially on a wet or downhill road. We treat early rear lockup as a need-now item. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.